Use JavaScript Standard Style

Introduce JavaScript Standard Style as project style rule,
and fixed all fail on backend code.

6 files changed, 1010 insertions, 1033 deletions

diff --git a/lib/models/author.js b/lib/models/author.js
index 0b0f149d..5e39c347 100644
--- a/lib/models/author.js
+++ b/lib/models/author.js
@@ -1,43 +1,37 @@
-"use strict";
-
 // external modules
-var Sequelize = require("sequelize");
-
-// core
-var logger = require("../logger.js");
+var Sequelize = require('sequelize')
 
 module.exports = function (sequelize, DataTypes) {
-    var Author = sequelize.define("Author", {
-        id: {
-            type: Sequelize.INTEGER,
-            primaryKey: true,
-            autoIncrement: true
-        },
-        color: {
-            type: DataTypes.STRING
-        }
-    }, {
-        indexes: [
-            {
-                unique: true,
-                fields: ['noteId', 'userId']
-            }
-        ],
-        classMethods: {
-            associate: function (models) {
-                Author.belongsTo(models.Note, {
-                    foreignKey: "noteId",
-                    as: "note",
-                    constraints: false
-                });
-                Author.belongsTo(models.User, {
-                    foreignKey: "userId",
-                    as: "user",
-                    constraints: false
-                });
-            }
-        }
-    });
-    
-    return Author;
-};
\ No newline at end of file
+  var Author = sequelize.define('Author', {
+    id: {
+      type: Sequelize.INTEGER,
+      primaryKey: true,
+      autoIncrement: true
+    },
+    color: {
+      type: DataTypes.STRING
+    }
+  }, {
+    indexes: [
+      {
+        unique: true,
+        fields: ['noteId', 'userId']
+      }
+    ],
+    classMethods: {
+      associate: function (models) {
+        Author.belongsTo(models.Note, {
+          foreignKey: 'noteId',
+          as: 'note',
+          constraints: false
+        })
+        Author.belongsTo(models.User, {
+          foreignKey: 'userId',
+          as: 'user',
+          constraints: false
+        })
+      }
+    }
+  })
+  return Author
+}
diff --git a/lib/models/index.js b/lib/models/index.js
index e83956e5..96babc2a 100644
--- a/lib/models/index.js
+++ b/lib/models/index.js
@@ -1,57 +1,55 @@
-"use strict";
-
 // external modules
-var fs = require("fs");
-var path = require("path");
-var Sequelize = require("sequelize");
+var fs = require('fs')
+var path = require('path')
+var Sequelize = require('sequelize')
 
 // core
-var config = require('../config.js');
-var logger = require("../logger.js");
+var config = require('../config.js')
+var logger = require('../logger.js')
 
-var dbconfig = config.db;
-dbconfig.logging = config.debug ? logger.info : false;
+var dbconfig = config.db
+dbconfig.logging = config.debug ? logger.info : false
 
-var sequelize = null;
+var sequelize = null
 
 // Heroku specific
-if (config.dburl)
-    sequelize = new Sequelize(config.dburl, dbconfig);
-else
-    sequelize = new Sequelize(dbconfig.database, dbconfig.username, dbconfig.password, dbconfig);
+if (config.dburl) {
+  sequelize = new Sequelize(config.dburl, dbconfig)
+} else {
+  sequelize = new Sequelize(dbconfig.database, dbconfig.username, dbconfig.password, dbconfig)
+}
 
 // [Postgres] Handling NULL bytes
 // https://github.com/sequelize/sequelize/issues/6485
-function stripNullByte(value) {
-    return value ? value.replace(/\u0000/g, "") : value;
+function stripNullByte (value) {
+  return value ? value.replace(/\u0000/g, '') : value
 }
-sequelize.stripNullByte = stripNullByte;
+sequelize.stripNullByte = stripNullByte
 
-function processData(data, _default, process) {
-    if (data === undefined) return data;
-    else return data === null ? _default : (process ? process(data) : data);
+function processData (data, _default, process) {
+  if (data === undefined) return data
+  else return data === null ? _default : (process ? process(data) : data)
 }
-sequelize.processData = processData;
+sequelize.processData = processData
 
-var db = {};
+var db = {}
 
-fs
-    .readdirSync(__dirname)
+fs.readdirSync(__dirname)
     .filter(function (file) {
-        return (file.indexOf(".") !== 0) && (file !== "index.js");
+      return (file.indexOf('.') !== 0) && (file !== 'index.js')
     })
     .forEach(function (file) {
-        var model = sequelize.import(path.join(__dirname, file));
-        db[model.name] = model;
-    });
+      var model = sequelize.import(path.join(__dirname, file))
+      db[model.name] = model
+    })
 
 Object.keys(db).forEach(function (modelName) {
-    if ("associate" in db[modelName]) {
-        db[modelName].associate(db);
-    }
-});
+  if ('associate' in db[modelName]) {
+    db[modelName].associate(db)
+  }
+})
 
-db.sequelize = sequelize;
-db.Sequelize = Sequelize;
+db.sequelize = sequelize
+db.Sequelize = Sequelize
 
-module.exports = db;
+module.exports = db
diff --git a/lib/models/note.js b/lib/models/note.js
index 8b38d3f9..bef9ee21 100644
--- a/lib/models/note.js
+++ b/lib/models/note.js
@@ -1,535 +1,524 @@
-"use strict";
-
 // external modules
-var fs = require('fs');
-var path = require('path');
-var LZString = require('lz-string');
-var md = require('markdown-it')();
-var metaMarked = require('meta-marked');
-var cheerio = require('cheerio');
-var shortId = require('shortid');
-var Sequelize = require("sequelize");
-var async = require('async');
-var moment = require('moment');
-var DiffMatchPatch = require('diff-match-patch');
-var dmp = new DiffMatchPatch();
-var S = require('string');
+var fs = require('fs')
+var path = require('path')
+var LZString = require('lz-string')
+var md = require('markdown-it')()
+var metaMarked = require('meta-marked')
+var cheerio = require('cheerio')
+var shortId = require('shortid')
+var Sequelize = require('sequelize')
+var async = require('async')
+var moment = require('moment')
+var DiffMatchPatch = require('diff-match-patch')
+var dmp = new DiffMatchPatch()
+var S = require('string')
 
 // core
-var config = require("../config.js");
-var logger = require("../logger.js");
+var config = require('../config.js')
+var logger = require('../logger.js')
 
-//ot
-var ot = require("../ot/index.js");
+// ot
+var ot = require('../ot/index.js')
 
 // permission types
-var permissionTypes = ["freely", "editable", "limited", "locked", "protected", "private"];
+var permissionTypes = ['freely', 'editable', 'limited', 'locked', 'protected', 'private']
 
 module.exports = function (sequelize, DataTypes) {
-    var Note = sequelize.define("Note", {
-        id: {
-            type: DataTypes.UUID,
-            primaryKey: true,
-            defaultValue: Sequelize.UUIDV4
-        },
-        shortid: {
-            type: DataTypes.STRING,
-            unique: true,
-            allowNull: false,
-            defaultValue: shortId.generate
-        },
-        alias: {
-            type: DataTypes.STRING,
-            unique: true
-        },
-        permission: {
-            type: DataTypes.ENUM,
-            values: permissionTypes
-        },
-        viewcount: {
-            type: DataTypes.INTEGER,
-            allowNull: false,
-            defaultValue: 0
-        },
-        title: {
-            type: DataTypes.TEXT,
-            get: function () {
-                return sequelize.processData(this.getDataValue('title'), "");
-            },
-            set: function (value) {
-                this.setDataValue('title', sequelize.stripNullByte(value));
-            }
-        },
-        content: {
-            type: DataTypes.TEXT,
-            get: function () {
-                return sequelize.processData(this.getDataValue('content'), "");
-            },
-            set: function (value) {
-                this.setDataValue('content', sequelize.stripNullByte(value));
-            }
-        },
-        authorship: {
-            type: DataTypes.TEXT,
-            get: function () {
-                return sequelize.processData(this.getDataValue('authorship'), [], JSON.parse);
-            },
-            set: function (value) {
-                this.setDataValue('authorship', JSON.stringify(value));
-            }
-        },
-        lastchangeAt: {
-            type: DataTypes.DATE
-        },
-        savedAt: {
-            type: DataTypes.DATE
+  var Note = sequelize.define('Note', {
+    id: {
+      type: DataTypes.UUID,
+      primaryKey: true,
+      defaultValue: Sequelize.UUIDV4
+    },
+    shortid: {
+      type: DataTypes.STRING,
+      unique: true,
+      allowNull: false,
+      defaultValue: shortId.generate
+    },
+    alias: {
+      type: DataTypes.STRING,
+      unique: true
+    },
+    permission: {
+      type: DataTypes.ENUM,
+      values: permissionTypes
+    },
+    viewcount: {
+      type: DataTypes.INTEGER,
+      allowNull: false,
+      defaultValue: 0
+    },
+    title: {
+      type: DataTypes.TEXT,
+      get: function () {
+        return sequelize.processData(this.getDataValue('title'), '')
+      },
+      set: function (value) {
+        this.setDataValue('title', sequelize.stripNullByte(value))
+      }
+    },
+    content: {
+      type: DataTypes.TEXT,
+      get: function () {
+        return sequelize.processData(this.getDataValue('content'), '')
+      },
+      set: function (value) {
+        this.setDataValue('content', sequelize.stripNullByte(value))
+      }
+    },
+    authorship: {
+      type: DataTypes.TEXT,
+      get: function () {
+        return sequelize.processData(this.getDataValue('authorship'), [], JSON.parse)
+      },
+      set: function (value) {
+        this.setDataValue('authorship', JSON.stringify(value))
+      }
+    },
+    lastchangeAt: {
+      type: DataTypes.DATE
+    },
+    savedAt: {
+      type: DataTypes.DATE
+    }
+  }, {
+    paranoid: true,
+    classMethods: {
+      associate: function (models) {
+        Note.belongsTo(models.User, {
+          foreignKey: 'ownerId',
+          as: 'owner',
+          constraints: false
+        })
+        Note.belongsTo(models.User, {
+          foreignKey: 'lastchangeuserId',
+          as: 'lastchangeuser',
+          constraints: false
+        })
+        Note.hasMany(models.Revision, {
+          foreignKey: 'noteId',
+          constraints: false
+        })
+        Note.hasMany(models.Author, {
+          foreignKey: 'noteId',
+          as: 'authors',
+          constraints: false
+        })
+      },
+      checkFileExist: function (filePath) {
+        try {
+          return fs.statSync(filePath).isFile()
+        } catch (err) {
+          return false
         }
-    }, {
-        paranoid: true,
-        classMethods: {
-            associate: function (models) {
-                Note.belongsTo(models.User, {
-                    foreignKey: "ownerId",
-                    as: "owner",
-                    constraints: false
-                });
-                Note.belongsTo(models.User, {
-                    foreignKey: "lastchangeuserId",
-                    as: "lastchangeuser",
-                    constraints: false
-                });
-                Note.hasMany(models.Revision, {
-                    foreignKey: "noteId",
-                    constraints: false
-                });
-                Note.hasMany(models.Author, {
-                    foreignKey: "noteId",
-                    as: "authors",
-                    constraints: false
-                });
-            },
-            checkFileExist: function (filePath) {
-                try {
-                    return fs.statSync(filePath).isFile();
-                } catch (err) {
-                    return false;
-                }
-            },
-            checkNoteIdValid: function (id) {
-                var uuidRegex = /^[0-9a-f]{8}-[0-9a-f]{4}-[1-5][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i;
-                var result = id.match(uuidRegex);
-                if (result && result.length == 1)
-                    return true;
-                else
-                    return false;
-            },
-            parseNoteId: function (noteId, callback) {
-                async.series({
-                    parseNoteIdByAlias: function (_callback) {
-                        // try to parse note id by alias (e.g. doc)
-                        Note.findOne({
-                            where: {
-                                alias: noteId
-                            }
+      },
+      checkNoteIdValid: function (id) {
+        var uuidRegex = /^[0-9a-f]{8}-[0-9a-f]{4}-[1-5][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i
+        var result = id.match(uuidRegex)
+        if (result && result.length === 1) { return true } else { return false }
+      },
+      parseNoteId: function (noteId, callback) {
+        async.series({
+          parseNoteIdByAlias: function (_callback) {
+            // try to parse note id by alias (e.g. doc)
+            Note.findOne({
+              where: {
+                alias: noteId
+              }
+            }).then(function (note) {
+              if (note) {
+                let filePath = path.join(config.docspath, noteId + '.md')
+                if (Note.checkFileExist(filePath)) {
+                  // if doc in filesystem have newer modified time than last change time
+                  // then will update the doc in db
+                  var fsModifiedTime = moment(fs.statSync(filePath).mtime)
+                  var dbModifiedTime = moment(note.lastchangeAt || note.createdAt)
+                  var body = fs.readFileSync(filePath, 'utf8')
+                  var contentLength = body.length
+                  var title = Note.parseNoteTitle(body)
+                  if (fsModifiedTime.isAfter(dbModifiedTime) && note.content !== body) {
+                    note.update({
+                      title: title,
+                      content: body,
+                      lastchangeAt: fsModifiedTime
+                    }).then(function (note) {
+                      sequelize.models.Revision.saveNoteRevision(note, function (err, revision) {
+                        if (err) return _callback(err, null)
+                        // update authorship on after making revision of docs
+                        var patch = dmp.patch_fromText(revision.patch)
+                        var operations = Note.transformPatchToOperations(patch, contentLength)
+                        var authorship = note.authorship
+                        for (let i = 0; i < operations.length; i++) {
+                          authorship = Note.updateAuthorshipByOperation(operations[i], null, authorship)
+                        }
+                        note.update({
+                          authorship: JSON.stringify(authorship)
                         }).then(function (note) {
-                            if (note) {
-                                var filePath = path.join(config.docspath, noteId + '.md');
-                                if (Note.checkFileExist(filePath)) {
-                                    // if doc in filesystem have newer modified time than last change time
-                                    // then will update the doc in db
-                                    var fsModifiedTime = moment(fs.statSync(filePath).mtime);
-                                    var dbModifiedTime = moment(note.lastchangeAt || note.createdAt);
-                                    var body = fs.readFileSync(filePath, 'utf8');
-                                    var contentLength = body.length;
-                                    var title = Note.parseNoteTitle(body);
-                                    if (fsModifiedTime.isAfter(dbModifiedTime) && note.content !== body) {
-                                        note.update({
-                                            title: title,
-                                            content: body,
-                                            lastchangeAt: fsModifiedTime
-                                        }).then(function (note) {
-                                            sequelize.models.Revision.saveNoteRevision(note, function (err, revision) {
-                                                if (err) return _callback(err, null);
-                                                // update authorship on after making revision of docs
-                                                var patch = dmp.patch_fromText(revision.patch);
-                                                var operations = Note.transformPatchToOperations(patch, contentLength);
-                                                var authorship = note.authorship;
-                                                for (var i = 0; i < operations.length; i++) {
-                                                    authorship = Note.updateAuthorshipByOperation(operations[i], null, authorship);
-                                                }
-                                                note.update({
-                                                    authorship: JSON.stringify(authorship)
-                                                }).then(function (note) {
-                                                    return callback(null, note.id);
-                                                }).catch(function (err) {
-                                                    return _callback(err, null);
-                                                });
-                                            });
-                                        }).catch(function (err) {
-                                            return _callback(err, null);
-                                        });
-                                    } else {
-                                        return callback(null, note.id);
-                                    }
-                                } else {
-                                    return callback(null, note.id);
-                                }
-                            } else {
-                                var filePath = path.join(config.docspath, noteId + '.md');
-                                if (Note.checkFileExist(filePath)) {
-                                    Note.create({
-                                        alias: noteId,
-                                        owner: null,
-                                        permission: 'locked'
-                                    }).then(function (note) {
-                                        return callback(null, note.id);
-                                    }).catch(function (err) {
-                                        return _callback(err, null);
-                                    });
-                                } else {
-                                    return _callback(null, null);
-                                }
-                            }
+                          return callback(null, note.id)
                         }).catch(function (err) {
-                            return _callback(err, null);
-                        });
-                    },
-                    parseNoteIdByLZString: function (_callback) {
-                        // try to parse note id by LZString Base64
-                        try {
-                            var id = LZString.decompressFromBase64(noteId);
-                            if (id && Note.checkNoteIdValid(id))
-                                return callback(null, id);
-                            else
-                                return _callback(null, null);
-                        } catch (err) {
-                            return _callback(err, null);
-                        }
-                    },
-                    parseNoteIdByShortId: function (_callback) {
-                        // try to parse note id by shortId
-                        try {
-                            if (shortId.isValid(noteId)) {
-                                Note.findOne({
-                                    where: {
-                                        shortid: noteId
-                                    }
-                                }).then(function (note) {
-                                    if (!note) return _callback(null, null);
-                                    return callback(null, note.id);
-                                }).catch(function (err) {
-                                    return _callback(err, null);
-                                });
-                            } else {
-                                return _callback(null, null);
-                            }
-                        } catch (err) {
-                            return _callback(err, null);
-                        }
-                    }
-                }, function (err, result) {
-                    if (err) {
-                        logger.error(err);
-                        return callback(err, null);
-                    }
-                    return callback(null, null);
-                });
-            },
-            parseNoteInfo: function (body) {
-                var parsed = Note.extractMeta(body);
-                var $ = cheerio.load(md.render(parsed.markdown));
-                return {
-                    title: Note.extractNoteTitle(parsed.meta, $),
-                    tags: Note.extractNoteTags(parsed.meta, $)
-                };
-            },
-            parseNoteTitle: function (body) {
-                var parsed = Note.extractMeta(body);
-                var $ = cheerio.load(md.render(parsed.markdown));
-                return Note.extractNoteTitle(parsed.meta, $);
-            },
-            extractNoteTitle: function (meta, $) {
-                var title = "";
-                if (meta.title && (typeof meta.title == "string" || typeof meta.title == "number")) {
-                    title = meta.title;
+                          return _callback(err, null)
+                        })
+                      })
+                    }).catch(function (err) {
+                      return _callback(err, null)
+                    })
+                  } else {
+                    return callback(null, note.id)
+                  }
                 } else {
-                    var h1s = $("h1");
-                    if (h1s.length > 0 && h1s.first().text().split('\n').length == 1)
-                        title = S(h1s.first().text()).stripTags().s;
+                  return callback(null, note.id)
                 }
-                if (!title) title = "Untitled";
-                return title;
-            },
-            generateDescription: function (markdown) {
-                return markdown.substr(0, 100).replace(/(?:\r\n|\r|\n)/g, ' ');
-            },
-            decodeTitle: function (title) {
-                return title ? title : 'Untitled';
-            },
-            generateWebTitle: function (title) {
-                title = !title || title == "Untitled" ? "HackMD - Collaborative markdown notes" : title + " - HackMD";
-                return title;
-            },
-            extractNoteTags: function (meta, $) {
-                var tags = [];
-                var rawtags = [];
-                if (meta.tags && (typeof meta.tags == "string" || typeof meta.tags == "number")) {
-                    var metaTags = ('' + meta.tags).split(',');
-                    for (var i = 0; i < metaTags.length; i++) {
-                        var text = metaTags[i].trim();
-                        if (text) rawtags.push(text);
-                    }
+              } else {
+                var filePath = path.join(config.docspath, noteId + '.md')
+                if (Note.checkFileExist(filePath)) {
+                  Note.create({
+                    alias: noteId,
+                    owner: null,
+                    permission: 'locked'
+                  }).then(function (note) {
+                    return callback(null, note.id)
+                  }).catch(function (err) {
+                    return _callback(err, null)
+                  })
                 } else {
-                    var h6s = $("h6");
-                    h6s.each(function (key, value) {
-                        if (/^tags/gmi.test($(value).text())) {
-                            var codes = $(value).find("code");
-                            for (var i = 0; i < codes.length; i++) {
-                                var text = S($(codes[i]).text().trim()).stripTags().s;
-                                if (text) rawtags.push(text);
-                            }
-                        }
-                    });
-                }
-                for (var i = 0; i < rawtags.length; i++) {
-                    var found = false;
-                    for (var j = 0; j < tags.length; j++) {
-                        if (tags[j] == rawtags[i]) {
-                            found = true;
-                            break;
-                        }
-                    }
-                    if (!found)
-                        tags.push(rawtags[i]);
-                }
-                return tags;
-            },
-            extractMeta: function (content) {
-                try {
-                    var obj = metaMarked(content);
-                    if (!obj.markdown) obj.markdown = "";
-                    if (!obj.meta) obj.meta = {};
-                } catch (err) {
-                    var obj = {
-                        markdown: content,
-                        meta: {}
-                    };
-                }
-                return obj;
-            },
-            parseMeta: function (meta) {
-                var _meta = {};
-                if (meta) {
-                    if (meta.title && (typeof meta.title == "string" || typeof meta.title == "number"))
-                        _meta.title = meta.title;
-                    if (meta.description && (typeof meta.description == "string" || typeof meta.description == "number"))
-                        _meta.description = meta.description;
-                    if (meta.robots && (typeof meta.robots == "string" || typeof meta.robots == "number"))
-                        _meta.robots = meta.robots;
-                    if (meta.GA && (typeof meta.GA == "string" || typeof meta.GA == "number"))
-                        _meta.GA = meta.GA;
-                    if (meta.disqus && (typeof meta.disqus == "string" || typeof meta.disqus == "number"))
-                        _meta.disqus = meta.disqus;
-                    if (meta.slideOptions && (typeof meta.slideOptions == "object"))
-                        _meta.slideOptions = meta.slideOptions;
+                  return _callback(null, null)
                 }
-                return _meta;
-            },
-            updateAuthorshipByOperation: function (operation, userId, authorships) {
-                var index = 0;
-                var timestamp = Date.now();
-                for (var i = 0; i < operation.length; i++) {
-                    var op = operation[i];
-                    if (ot.TextOperation.isRetain(op)) {
-                        index += op;
-                    } else if (ot.TextOperation.isInsert(op)) {
-                        var opStart = index;
-                        var opEnd = index + op.length;
-                        var inserted = false;
-                        // authorship format: [userId, startPos, endPos, createdAt, updatedAt]
-                        if (authorships.length <= 0) authorships.push([userId, opStart, opEnd, timestamp, timestamp]);
-                        else {
-                            for (var j = 0; j < authorships.length; j++) {
-                                var authorship = authorships[j];
-                                if (!inserted) {
-                                    var nextAuthorship = authorships[j + 1] || -1;
-                                    if (nextAuthorship != -1 && nextAuthorship[1] >= opEnd || j >= authorships.length - 1) {
-                                        if (authorship[1] < opStart && authorship[2] > opStart) {
-                                            // divide
-                                            var postLength = authorship[2] - opStart;
-                                            authorship[2] = opStart;
-                                            authorship[4] = timestamp;
-                                            authorships.splice(j + 1, 0, [userId, opStart, opEnd, timestamp, timestamp]);
-                                            authorships.splice(j + 2, 0, [authorship[0], opEnd, opEnd + postLength, authorship[3], timestamp]);
-                                            j += 2;
-                                            inserted = true;
-                                        } else if (authorship[1] >= opStart) {
-                                            authorships.splice(j, 0, [userId, opStart, opEnd, timestamp, timestamp]);
-                                            j += 1;
-                                            inserted = true;
-                                        } else if (authorship[2] <= opStart) {
-                                            authorships.splice(j + 1, 0, [userId, opStart, opEnd, timestamp, timestamp]);
-                                            j += 1;
-                                            inserted = true;
-                                        }
-                                    }
-                                }
-                                if (authorship[1] >= opStart) {
-                                    authorship[1] += op.length;
-                                    authorship[2] += op.length;
-                                }
-                            }
-                        }
-                        index += op.length;
-                    } else if (ot.TextOperation.isDelete(op)) {
-                        var opStart = index;
-                        var opEnd = index - op;
-                        if (operation.length == 1) {
-                            authorships = [];
-                        } else if (authorships.length > 0) {
-                            for (var j = 0; j < authorships.length; j++) {
-                                var authorship = authorships[j];
-                                if (authorship[1] >= opStart && authorship[1] <= opEnd && authorship[2] >= opStart && authorship[2] <= opEnd) {
-                                    authorships.splice(j, 1);
-                                    j -= 1;
-                                } else if (authorship[1] < opStart && authorship[1] < opEnd && authorship[2] > opStart && authorship[2] > opEnd) {
-                                    authorship[2] += op;
-                                    authorship[4] = timestamp;
-                                } else if (authorship[2] >= opStart && authorship[2] <= opEnd) {
-                                    authorship[2] = opStart;
-                                    authorship[4] = timestamp;
-                                } else if (authorship[1] >= opStart && authorship[1] <= opEnd) {
-                                    authorship[1] = opEnd;
-                                    authorship[4] = timestamp;
-                                }
-                                if (authorship[1] >= opEnd) {
-                                    authorship[1] += op;
-                                    authorship[2] += op;
-                                }
-                            }
-                        }
-                        index += op;
-                    }
-                }
-                // merge
-                for (var j = 0; j < authorships.length; j++) {
-                    var authorship = authorships[j];
-                    for (var k = j + 1; k < authorships.length; k++) {
-                        var nextAuthorship = authorships[k];
-                        if (nextAuthorship && authorship[0] === nextAuthorship[0] && authorship[2] === nextAuthorship[1]) {
-                            var minTimestamp = Math.min(authorship[3], nextAuthorship[3]);
-                            var maxTimestamp = Math.max(authorship[3], nextAuthorship[3]);
-                            authorships.splice(j, 1, [authorship[0], authorship[1], nextAuthorship[2], minTimestamp, maxTimestamp]);
-                            authorships.splice(k, 1);
-                            j -= 1;
-                            break;
-                        }
-                    }
-                }
-                // clear
-                for (var j = 0; j < authorships.length; j++) {
-                    var authorship = authorships[j];
-                    if (!authorship[0]) {
-                        authorships.splice(j, 1);
-                        j -= 1;
+              }
+            }).catch(function (err) {
+              return _callback(err, null)
+            })
+          },
+          parseNoteIdByLZString: function (_callback) {
+            // try to parse note id by LZString Base64
+            try {
+              var id = LZString.decompressFromBase64(noteId)
+              if (id && Note.checkNoteIdValid(id)) { return callback(null, id) } else { return _callback(null, null) }
+            } catch (err) {
+              return _callback(err, null)
+            }
+          },
+          parseNoteIdByShortId: function (_callback) {
+            // try to parse note id by shortId
+            try {
+              if (shortId.isValid(noteId)) {
+                Note.findOne({
+                  where: {
+                    shortid: noteId
+                  }
+                }).then(function (note) {
+                  if (!note) return _callback(null, null)
+                  return callback(null, note.id)
+                }).catch(function (err) {
+                  return _callback(err, null)
+                })
+              } else {
+                return _callback(null, null)
+              }
+            } catch (err) {
+              return _callback(err, null)
+            }
+          }
+        }, function (err, result) {
+          if (err) {
+            logger.error(err)
+            return callback(err, null)
+          }
+          return callback(null, null)
+        })
+      },
+      parseNoteInfo: function (body) {
+        var parsed = Note.extractMeta(body)
+        var $ = cheerio.load(md.render(parsed.markdown))
+        return {
+          title: Note.extractNoteTitle(parsed.meta, $),
+          tags: Note.extractNoteTags(parsed.meta, $)
+        }
+      },
+      parseNoteTitle: function (body) {
+        var parsed = Note.extractMeta(body)
+        var $ = cheerio.load(md.render(parsed.markdown))
+        return Note.extractNoteTitle(parsed.meta, $)
+      },
+      extractNoteTitle: function (meta, $) {
+        var title = ''
+        if (meta.title && (typeof meta.title === 'string' || typeof meta.title === 'number')) {
+          title = meta.title
+        } else {
+          var h1s = $('h1')
+          if (h1s.length > 0 && h1s.first().text().split('\n').length === 1) { title = S(h1s.first().text()).stripTags().s }
+        }
+        if (!title) title = 'Untitled'
+        return title
+      },
+      generateDescription: function (markdown) {
+        return markdown.substr(0, 100).replace(/(?:\r\n|\r|\n)/g, ' ')
+      },
+      decodeTitle: function (title) {
+        return title || 'Untitled'
+      },
+      generateWebTitle: function (title) {
+        title = !title || title === 'Untitled' ? 'HackMD - Collaborative markdown notes' : title + ' - HackMD'
+        return title
+      },
+      extractNoteTags: function (meta, $) {
+        var tags = []
+        var rawtags = []
+        if (meta.tags && (typeof meta.tags === 'string' || typeof meta.tags === 'number')) {
+          var metaTags = ('' + meta.tags).split(',')
+          for (let i = 0; i < metaTags.length; i++) {
+            var text = metaTags[i].trim()
+            if (text) rawtags.push(text)
+          }
+        } else {
+          var h6s = $('h6')
+          h6s.each(function (key, value) {
+            if (/^tags/gmi.test($(value).text())) {
+              var codes = $(value).find('code')
+              for (let i = 0; i < codes.length; i++) {
+                var text = S($(codes[i]).text().trim()).stripTags().s
+                if (text) rawtags.push(text)
+              }
+            }
+          })
+        }
+        for (let i = 0; i < rawtags.length; i++) {
+          var found = false
+          for (let j = 0; j < tags.length; j++) {
+            if (tags[j] === rawtags[i]) {
+              found = true
+              break
+            }
+          }
+          if (!found) { tags.push(rawtags[i]) }
+        }
+        return tags
+      },
+      extractMeta: function (content) {
+        var obj = null
+        try {
+          obj = metaMarked(content)
+          if (!obj.markdown) obj.markdown = ''
+          if (!obj.meta) obj.meta = {}
+        } catch (err) {
+          obj = {
+            markdown: content,
+            meta: {}
+          }
+        }
+        return obj
+      },
+      parseMeta: function (meta) {
+        var _meta = {}
+        if (meta) {
+          if (meta.title && (typeof meta.title === 'string' || typeof meta.title === 'number')) { _meta.title = meta.title }
+          if (meta.description && (typeof meta.description === 'string' || typeof meta.description === 'number')) { _meta.description = meta.description }
+          if (meta.robots && (typeof meta.robots === 'string' || typeof meta.robots === 'number')) { _meta.robots = meta.robots }
+          if (meta.GA && (typeof meta.GA === 'string' || typeof meta.GA === 'number')) { _meta.GA = meta.GA }
+          if (meta.disqus && (typeof meta.disqus === 'string' || typeof meta.disqus === 'number')) { _meta.disqus = meta.disqus }
+          if (meta.slideOptions && (typeof meta.slideOptions === 'object')) { _meta.slideOptions = meta.slideOptions }
+        }
+        return _meta
+      },
+      updateAuthorshipByOperation: function (operation, userId, authorships) {
+        var index = 0
+        var timestamp = Date.now()
+        for (let i = 0; i < operation.length; i++) {
+          var op = operation[i]
+          if (ot.TextOperation.isRetain(op)) {
+            index += op
+          } else if (ot.TextOperation.isInsert(op)) {
+            let opStart = index
+            let opEnd = index + op.length
+            var inserted = false
+            // authorship format: [userId, startPos, endPos, createdAt, updatedAt]
+            if (authorships.length <= 0) authorships.push([userId, opStart, opEnd, timestamp, timestamp])
+            else {
+              for (let j = 0; j < authorships.length; j++) {
+                let authorship = authorships[j]
+                if (!inserted) {
+                  let nextAuthorship = authorships[j + 1] || -1
+                  if ((nextAuthorship !== -1 && nextAuthorship[1] >= opEnd) || j >= authorships.length - 1) {
+                    if (authorship[1] < opStart && authorship[2] > opStart) {
+                      // divide
+                      let postLength = authorship[2] - opStart
+                      authorship[2] = opStart
+                      authorship[4] = timestamp
+                      authorships.splice(j + 1, 0, [userId, opStart, opEnd, timestamp, timestamp])
+                      authorships.splice(j + 2, 0, [authorship[0], opEnd, opEnd + postLength, authorship[3], timestamp])
+                      j += 2
+                      inserted = true
+                    } else if (authorship[1] >= opStart) {
+                      authorships.splice(j, 0, [userId, opStart, opEnd, timestamp, timestamp])
+                      j += 1
+                      inserted = true
+                    } else if (authorship[2] <= opStart) {
+                      authorships.splice(j + 1, 0, [userId, opStart, opEnd, timestamp, timestamp])
+                      j += 1
+                      inserted = true
                     }
+                  }
                 }
-                return authorships;
-            },
-            transformPatchToOperations: function (patch, contentLength) {
-                var operations = [];
-                if (patch.length > 0) {
-                    // calculate original content length
-                    for (var j = patch.length - 1; j >= 0; j--) {
-                        var p = patch[j];
-                        for (var i = 0; i < p.diffs.length; i++) {
-                            var diff = p.diffs[i];
-                            switch(diff[0]) {
-                                case 1: // insert
-                                    contentLength -= diff[1].length;
-                                break;
-                                case -1: // delete
-                                    contentLength += diff[1].length;
-                                break;
-                            }
-                        }
-                    }
-                    // generate operations
-                    var bias = 0;
-                    var lengthBias = 0;
-                    for (var j = 0; j < patch.length; j++) {
-                        var operation = [];
-                        var p = patch[j];
-                        var currIndex = p.start1;
-                        var currLength = contentLength - bias;
-                        for (var i = 0; i < p.diffs.length; i++) {
-                            var diff = p.diffs[i];
-                            switch(diff[0]) {
-                                case 0: // retain
-                                    if (i == 0) // first
-                                        operation.push(currIndex + diff[1].length);
-                                    else if (i != p.diffs.length - 1) // mid
-                                        operation.push(diff[1].length);
-                                    else // last
-                                        operation.push(currLength + lengthBias - currIndex);
-                                    currIndex += diff[1].length;
-                                break;
-                                case 1: // insert
-                                    operation.push(diff[1]);
-                                    lengthBias += diff[1].length;
-                                    currIndex += diff[1].length;
-                                break;
-                                case -1: // delete
-                                    operation.push(-diff[1].length);
-                                    bias += diff[1].length;
-                                    currIndex += diff[1].length;
-                                break;
-                            }
-                        }
-                        operations.push(operation);
-                    }
+                if (authorship[1] >= opStart) {
+                  authorship[1] += op.length
+                  authorship[2] += op.length
                 }
-                return operations;
+              }
             }
-        },
-        hooks: {
-            beforeCreate: function (note, options, callback) {
-                // if no content specified then use default note
-                if (!note.content) {
-                    var body = null;
-                    var filePath = null;
-                    if (!note.alias) {
-                        filePath = config.defaultnotepath;
-                    } else {
-                        filePath = path.join(config.docspath, note.alias + '.md');
-                    }
-                    if (Note.checkFileExist(filePath)) {
-                        var fsCreatedTime = moment(fs.statSync(filePath).ctime);
-                        body = fs.readFileSync(filePath, 'utf8');
-                        note.title = Note.parseNoteTitle(body);
-                        note.content = body;
-                        if (filePath !== config.defaultnotepath) {
-                            note.createdAt = fsCreatedTime;
-                        }
-                    }
+            index += op.length
+          } else if (ot.TextOperation.isDelete(op)) {
+            let opStart = index
+            let opEnd = index - op
+            if (operation.length === 1) {
+              authorships = []
+            } else if (authorships.length > 0) {
+              for (let j = 0; j < authorships.length; j++) {
+                let authorship = authorships[j]
+                if (authorship[1] >= opStart && authorship[1] <= opEnd && authorship[2] >= opStart && authorship[2] <= opEnd) {
+                  authorships.splice(j, 1)
+                  j -= 1
+                } else if (authorship[1] < opStart && authorship[1] < opEnd && authorship[2] > opStart && authorship[2] > opEnd) {
+                  authorship[2] += op
+                  authorship[4] = timestamp
+                } else if (authorship[2] >= opStart && authorship[2] <= opEnd) {
+                  authorship[2] = opStart
+                  authorship[4] = timestamp
+                } else if (authorship[1] >= opStart && authorship[1] <= opEnd) {
+                  authorship[1] = opEnd
+                  authorship[4] = timestamp
                 }
-                // if no permission specified and have owner then give default permission in config, else default permission is freely
-                if (!note.permission) {
-                    if (note.ownerId) {
-                        note.permission = config.defaultpermission;
-                    } else {
-                        note.permission = "freely";
-                    }
+                if (authorship[1] >= opEnd) {
+                  authorship[1] += op
+                  authorship[2] += op
                 }
-                return callback(null, note);
-            },
-            afterCreate: function (note, options, callback) {
-                sequelize.models.Revision.saveNoteRevision(note, function (err, revision) {
-                    callback(err, note);
-                });
+              }
+            }
+            index += op
+          }
+        }
+        // merge
+        for (let j = 0; j < authorships.length; j++) {
+          let authorship = authorships[j]
+          for (let k = j + 1; k < authorships.length; k++) {
+            let nextAuthorship = authorships[k]
+            if (nextAuthorship && authorship[0] === nextAuthorship[0] && authorship[2] === nextAuthorship[1]) {
+              let minTimestamp = Math.min(authorship[3], nextAuthorship[3])
+              let maxTimestamp = Math.max(authorship[3], nextAuthorship[3])
+              authorships.splice(j, 1, [authorship[0], authorship[1], nextAuthorship[2], minTimestamp, maxTimestamp])
+              authorships.splice(k, 1)
+              j -= 1
+              break
+            }
+          }
+        }
+        // clear
+        for (let j = 0; j < authorships.length; j++) {
+          let authorship = authorships[j]
+          if (!authorship[0]) {
+            authorships.splice(j, 1)
+            j -= 1
+          }
+        }
+        return authorships
+      },
+      transformPatchToOperations: function (patch, contentLength) {
+        var operations = []
+        if (patch.length > 0) {
+          // calculate original content length
+          for (let j = patch.length - 1; j >= 0; j--) {
+            var p = patch[j]
+            for (let i = 0; i < p.diffs.length; i++) {
+              var diff = p.diffs[i]
+              switch (diff[0]) {
+                case 1: // insert
+                  contentLength -= diff[1].length
+                  break
+                case -1: // delete
+                  contentLength += diff[1].length
+                  break
+              }
+            }
+          }
+          // generate operations
+          var bias = 0
+          var lengthBias = 0
+          for (let j = 0; j < patch.length; j++) {
+            var operation = []
+            let p = patch[j]
+            var currIndex = p.start1
+            var currLength = contentLength - bias
+            for (let i = 0; i < p.diffs.length; i++) {
+              let diff = p.diffs[i]
+              switch (diff[0]) {
+                case 0: // retain
+                  if (i === 0) {
+                    // first
+                    operation.push(currIndex + diff[1].length)
+                  } else if (i !== p.diffs.length - 1) {
+                    // mid
+                    operation.push(diff[1].length)
+                  } else {
+                    // last
+                    operation.push(currLength + lengthBias - currIndex)
+                  }
+                  currIndex += diff[1].length
+                  break
+                case 1: // insert
+                  operation.push(diff[1])
+                  lengthBias += diff[1].length
+                  currIndex += diff[1].length
+                  break
+                case -1: // delete
+                  operation.push(-diff[1].length)
+                  bias += diff[1].length
+                  currIndex += diff[1].length
+                  break
+              }
             }
+            operations.push(operation)
+          }
+        }
+        return operations
+      }
+    },
+    hooks: {
+      beforeCreate: function (note, options, callback) {
+        // if no content specified then use default note
+        if (!note.content) {
+          var body = null
+          let filePath = null
+          if (!note.alias) {
+            filePath = config.defaultnotepath
+          } else {
+            filePath = path.join(config.docspath, note.alias + '.md')
+          }
+          if (Note.checkFileExist(filePath)) {
+            var fsCreatedTime = moment(fs.statSync(filePath).ctime)
+            body = fs.readFileSync(filePath, 'utf8')
+            note.title = Note.parseNoteTitle(body)
+            note.content = body
+            if (filePath !== config.defaultnotepath) {
+              note.createdAt = fsCreatedTime
+            }
+          }
+        }
+        // if no permission specified and have owner then give default permission in config, else default permission is freely
+        if (!note.permission) {
+          if (note.ownerId) {
+            note.permission = config.defaultpermission
+          } else {
+            note.permission = 'freely'
+          }
         }
-    });
+        return callback(null, note)
+      },
+      afterCreate: function (note, options, callback) {
+        sequelize.models.Revision.saveNoteRevision(note, function (err, revision) {
+          callback(err, note)
+        })
+      }
+    }
+  })
 
-    return Note;
-};
+  return Note
+}
diff --git a/lib/models/revision.js b/lib/models/revision.js
index c7360fed..d8dab30a 100644
--- a/lib/models/revision.js
+++ b/lib/models/revision.js
@@ -1,306 +1,306 @@
-"use strict";
-
 // external modules
-var Sequelize = require("sequelize");
-var async = require('async');
-var moment = require('moment');
-var childProcess = require('child_process');
-var shortId = require('shortid');
+var Sequelize = require('sequelize')
+var async = require('async')
+var moment = require('moment')
+var childProcess = require('child_process')
+var shortId = require('shortid')
 
 // core
-var config = require("../config.js");
-var logger = require("../logger.js");
+var config = require('../config.js')
+var logger = require('../logger.js')
 
-var dmpWorker = createDmpWorker();
-var dmpCallbackCache = {};
+var dmpWorker = createDmpWorker()
+var dmpCallbackCache = {}
 
-function createDmpWorker() {
-    var worker = childProcess.fork("./lib/workers/dmpWorker.js", {
-        stdio: 'ignore'
-    });
-    if (config.debug) logger.info('dmp worker process started');
-    worker.on('message', function (data) {
-        if (!data || !data.msg || !data.cacheKey) {
-            return logger.error('dmp worker error: not enough data on message');
-        }
-        var cacheKey = data.cacheKey;
-        switch(data.msg) {
-            case 'error':
-                dmpCallbackCache[cacheKey](data.error, null);
-                break;
-            case 'check':
-                dmpCallbackCache[cacheKey](null, data.result);
-                break;
-        }
-        delete dmpCallbackCache[cacheKey];
-    });
-    worker.on('close', function (code) {
-        dmpWorker = null;
-        if (config.debug) logger.info('dmp worker process exited with code ' + code);
-    });
-    return worker;
+function createDmpWorker () {
+  var worker = childProcess.fork('./lib/workers/dmpWorker.js', {
+    stdio: 'ignore'
+  })
+  if (config.debug) logger.info('dmp worker process started')
+  worker.on('message', function (data) {
+    if (!data || !data.msg || !data.cacheKey) {
+      return logger.error('dmp worker error: not enough data on message')
+    }
+    var cacheKey = data.cacheKey
+    switch (data.msg) {
+      case 'error':
+        dmpCallbackCache[cacheKey](data.error, null)
+        break
+      case 'check':
+        dmpCallbackCache[cacheKey](null, data.result)
+        break
+    }
+    delete dmpCallbackCache[cacheKey]
+  })
+  worker.on('close', function (code) {
+    dmpWorker = null
+    if (config.debug) logger.info('dmp worker process exited with code ' + code)
+  })
+  return worker
 }
 
-function sendDmpWorker(data, callback) {
-    if (!dmpWorker) dmpWorker = createDmpWorker();
-    var cacheKey = Date.now() + '_' + shortId.generate();
-    dmpCallbackCache[cacheKey] = callback;
-    data = Object.assign(data, {
-        cacheKey: cacheKey
-    });
-    dmpWorker.send(data);
+function sendDmpWorker (data, callback) {
+  if (!dmpWorker) dmpWorker = createDmpWorker()
+  var cacheKey = Date.now() + '_' + shortId.generate()
+  dmpCallbackCache[cacheKey] = callback
+  data = Object.assign(data, {
+    cacheKey: cacheKey
+  })
+  dmpWorker.send(data)
 }
 
 module.exports = function (sequelize, DataTypes) {
-    var Revision = sequelize.define("Revision", {
-        id: {
-            type: DataTypes.UUID,
-            primaryKey: true,
-            defaultValue: Sequelize.UUIDV4
-        },
-        patch: {
-            type: DataTypes.TEXT,
-            get: function () {
-                return sequelize.processData(this.getDataValue('patch'), "");
-            },
-            set: function (value) {
-                this.setDataValue('patch', sequelize.stripNullByte(value));
-            }
-        },
-        lastContent: {
-            type: DataTypes.TEXT,
-            get: function () {
-                return sequelize.processData(this.getDataValue('lastContent'), "");
+  var Revision = sequelize.define('Revision', {
+    id: {
+      type: DataTypes.UUID,
+      primaryKey: true,
+      defaultValue: Sequelize.UUIDV4
+    },
+    patch: {
+      type: DataTypes.TEXT,
+      get: function () {
+        return sequelize.processData(this.getDataValue('patch'), '')
+      },
+      set: function (value) {
+        this.setDataValue('patch', sequelize.stripNullByte(value))
+      }
+    },
+    lastContent: {
+      type: DataTypes.TEXT,
+      get: function () {
+        return sequelize.processData(this.getDataValue('lastContent'), '')
+      },
+      set: function (value) {
+        this.setDataValue('lastContent', sequelize.stripNullByte(value))
+      }
+    },
+    content: {
+      type: DataTypes.TEXT,
+      get: function () {
+        return sequelize.processData(this.getDataValue('content'), '')
+      },
+      set: function (value) {
+        this.setDataValue('content', sequelize.stripNullByte(value))
+      }
+    },
+    length: {
+      type: DataTypes.INTEGER
+    },
+    authorship: {
+      type: DataTypes.TEXT,
+      get: function () {
+        return sequelize.processData(this.getDataValue('authorship'), [], JSON.parse)
+      },
+      set: function (value) {
+        this.setDataValue('authorship', value ? JSON.stringify(value) : value)
+      }
+    }
+  }, {
+    classMethods: {
+      associate: function (models) {
+        Revision.belongsTo(models.Note, {
+          foreignKey: 'noteId',
+          as: 'note',
+          constraints: false
+        })
+      },
+      getNoteRevisions: function (note, callback) {
+        Revision.findAll({
+          where: {
+            noteId: note.id
+          },
+          order: '"createdAt" DESC'
+        }).then(function (revisions) {
+          var data = []
+          for (var i = 0, l = revisions.length; i < l; i++) {
+            var revision = revisions[i]
+            data.push({
+              time: moment(revision.createdAt).valueOf(),
+              length: revision.length
+            })
+          }
+          callback(null, data)
+        }).catch(function (err) {
+          callback(err, null)
+        })
+      },
+      getPatchedNoteRevisionByTime: function (note, time, callback) {
+        // find all revisions to prepare for all possible calculation
+        Revision.findAll({
+          where: {
+            noteId: note.id
+          },
+          order: '"createdAt" DESC'
+        }).then(function (revisions) {
+          if (revisions.length <= 0) return callback(null, null)
+          // measure target revision position
+          Revision.count({
+            where: {
+              noteId: note.id,
+              createdAt: {
+                $gte: time
+              }
             },
-            set: function (value) {
-                this.setDataValue('lastContent', sequelize.stripNullByte(value));
+            order: '"createdAt" DESC'
+          }).then(function (count) {
+            if (count <= 0) return callback(null, null)
+            sendDmpWorker({
+              msg: 'get revision',
+              revisions: revisions,
+              count: count
+            }, callback)
+          }).catch(function (err) {
+            return callback(err, null)
+          })
+        }).catch(function (err) {
+          return callback(err, null)
+        })
+      },
+      checkAllNotesRevision: function (callback) {
+        Revision.saveAllNotesRevision(function (err, notes) {
+          if (err) return callback(err, null)
+          if (!notes || notes.length <= 0) {
+            return callback(null, notes)
+          } else {
+            Revision.checkAllNotesRevision(callback)
+          }
+        })
+      },
+      saveAllNotesRevision: function (callback) {
+        sequelize.models.Note.findAll({
+          // query all notes that need to save for revision
+          where: {
+            $and: [
+              {
+                lastchangeAt: {
+                  $or: {
+                    $eq: null,
+                    $and: {
+                      $ne: null,
+                      $gt: sequelize.col('createdAt')
+                    }
+                  }
+                }
+              },
+              {
+                savedAt: {
+                  $or: {
+                    $eq: null,
+                    $lt: sequelize.col('lastchangeAt')
+                  }
+                }
+              }
+            ]
+          }
+        }).then(function (notes) {
+          if (notes.length <= 0) return callback(null, notes)
+          var savedNotes = []
+          async.each(notes, function (note, _callback) {
+            // revision saving policy: note not been modified for 5 mins or not save for 10 mins
+            if (note.lastchangeAt && note.savedAt) {
+              var lastchangeAt = moment(note.lastchangeAt)
+              var savedAt = moment(note.savedAt)
+              if (moment().isAfter(lastchangeAt.add(5, 'minutes'))) {
+                savedNotes.push(note)
+                Revision.saveNoteRevision(note, _callback)
+              } else if (lastchangeAt.isAfter(savedAt.add(10, 'minutes'))) {
+                savedNotes.push(note)
+                Revision.saveNoteRevision(note, _callback)
+              } else {
+                return _callback(null, null)
+              }
+            } else {
+              savedNotes.push(note)
+              Revision.saveNoteRevision(note, _callback)
             }
-        },
-        content: {
-            type: DataTypes.TEXT,
-            get: function () {
-                return sequelize.processData(this.getDataValue('content'), "");
-            },
-            set: function (value) {
-                this.setDataValue('content', sequelize.stripNullByte(value));
+          }, function (err) {
+            if (err) {
+              return callback(err, null)
             }
-        },
-        length: {
-            type: DataTypes.INTEGER
-        },
-        authorship: {
-            type: DataTypes.TEXT,
-            get: function () {
-                return sequelize.processData(this.getDataValue('authorship'), [], JSON.parse);
-            },
-            set: function (value) {
-                this.setDataValue('authorship', value ? JSON.stringify(value) : value);
-            }
-        }
-    }, {
-        classMethods: {
-            associate: function (models) {
-                Revision.belongsTo(models.Note, {
-                    foreignKey: "noteId",
-                    as: "note",
-                    constraints: false
-                });
-            },
-            getNoteRevisions: function (note, callback) {
-                Revision.findAll({
-                    where: {
-                        noteId: note.id
-                    },
-                    order: '"createdAt" DESC'
-                }).then(function (revisions) {
-                    var data = [];
-                    for (var i = 0, l = revisions.length; i < l; i++) {
-                        var revision = revisions[i];
-                        data.push({
-                            time: moment(revision.createdAt).valueOf(),
-                            length: revision.length
-                        });
-                    }
-                    callback(null, data);
-                }).catch(function (err) {
-                    callback(err, null);
-                });
-            },
-            getPatchedNoteRevisionByTime: function (note, time, callback) {
-                // find all revisions to prepare for all possible calculation
-                Revision.findAll({
-                    where: {
-                        noteId: note.id
-                    },
-                    order: '"createdAt" DESC'
-                }).then(function (revisions) {
-                    if (revisions.length <= 0) return callback(null, null);
-                    // measure target revision position 
-                    Revision.count({
-                        where: {
-                            noteId: note.id,
-                            createdAt: {
-                                $gte: time
-                            }
-                        },
-                        order: '"createdAt" DESC'
-                    }).then(function (count) {
-                        if (count <= 0) return callback(null, null);
-                        sendDmpWorker({
-                            msg: 'get revision',
-                            revisions: revisions,
-                            count: count
-                        }, callback);
-                    }).catch(function (err) {
-                        return callback(err, null);
-                    });
+            // return null when no notes need saving at this moment but have delayed tasks to be done
+            var result = ((savedNotes.length === 0) && (notes.length > savedNotes.length)) ? null : savedNotes
+            return callback(null, result)
+          })
+        }).catch(function (err) {
+          return callback(err, null)
+        })
+      },
+      saveNoteRevision: function (note, callback) {
+        Revision.findAll({
+          where: {
+            noteId: note.id
+          },
+          order: '"createdAt" DESC'
+        }).then(function (revisions) {
+          if (revisions.length <= 0) {
+            // if no revision available
+            Revision.create({
+              noteId: note.id,
+              lastContent: note.content,
+              length: note.content.length,
+              authorship: note.authorship
+            }).then(function (revision) {
+              Revision.finishSaveNoteRevision(note, revision, callback)
+            }).catch(function (err) {
+              return callback(err, null)
+            })
+          } else {
+            var latestRevision = revisions[0]
+            var lastContent = latestRevision.content || latestRevision.lastContent
+            var content = note.content
+            sendDmpWorker({
+              msg: 'create patch',
+              lastDoc: lastContent,
+              currDoc: content
+            }, function (err, patch) {
+              if (err) logger.error('save note revision error', err)
+              if (!patch) {
+                // if patch is empty (means no difference) then just update the latest revision updated time
+                latestRevision.changed('updatedAt', true)
+                latestRevision.update({
+                  updatedAt: Date.now()
+                }).then(function (revision) {
+                  Revision.finishSaveNoteRevision(note, revision, callback)
                 }).catch(function (err) {
-                    return callback(err, null);
-                });
-            },
-            checkAllNotesRevision: function (callback) {
-                Revision.saveAllNotesRevision(function (err, notes) {
-                    if (err) return callback(err, null);
-                    if (!notes || notes.length <= 0) {
-                        return callback(null, notes);
-                    } else {
-                        Revision.checkAllNotesRevision(callback);
-                    }
-                });
-            },
-            saveAllNotesRevision: function (callback) {
-                sequelize.models.Note.findAll({
-                    // query all notes that need to save for revision
-                    where: {
-                        $and: [
-                            {
-                                lastchangeAt: {
-                                    $or: {
-                                        $eq: null,
-                                        $and: {
-                                            $ne: null,
-                                            $gt: sequelize.col('createdAt')
-                                        }
-                                    }
-                                }
-                            },
-                            {
-                                savedAt: {
-                                    $or: {
-                                        $eq: null,
-                                        $lt: sequelize.col('lastchangeAt')
-                                    }
-                                }
-                            }
-                        ]
-                    }
-                }).then(function (notes) {
-                    if (notes.length <= 0) return callback(null, notes);
-                    var savedNotes = [];
-                    async.each(notes, function (note, _callback) {
-                        // revision saving policy: note not been modified for 5 mins or not save for 10 mins
-                        if (note.lastchangeAt && note.savedAt) {
-                            var lastchangeAt = moment(note.lastchangeAt);
-                            var savedAt = moment(note.savedAt);
-                            if (moment().isAfter(lastchangeAt.add(5, 'minutes'))) {
-                                savedNotes.push(note);
-                                Revision.saveNoteRevision(note, _callback);
-                            } else if (lastchangeAt.isAfter(savedAt.add(10, 'minutes'))) {
-                                savedNotes.push(note);
-                                Revision.saveNoteRevision(note, _callback);
-                            } else {
-                                return _callback(null, null);
-                            }
-                        } else {
-                            savedNotes.push(note);
-                            Revision.saveNoteRevision(note, _callback);
-                        }
-                    }, function (err) {
-                        if (err) return callback(err, null);
-                        // return null when no notes need saving at this moment but have delayed tasks to be done 
-                        var result = ((savedNotes.length == 0) && (notes.length > savedNotes.length)) ? null : savedNotes;
-                        return callback(null, result);
-                    });
+                  return callback(err, null)
+                })
+              } else {
+                Revision.create({
+                  noteId: note.id,
+                  patch: patch,
+                  content: note.content,
+                  length: note.content.length,
+                  authorship: note.authorship
+                }).then(function (revision) {
+                  // clear last revision content to reduce db size
+                  latestRevision.update({
+                    content: null
+                  }).then(function () {
+                    Revision.finishSaveNoteRevision(note, revision, callback)
+                  }).catch(function (err) {
+                    return callback(err, null)
+                  })
                 }).catch(function (err) {
-                    return callback(err, null);
-                });
-            },
-            saveNoteRevision: function (note, callback) {
-                Revision.findAll({
-                    where: {
-                        noteId: note.id
-                    },
-                    order: '"createdAt" DESC'
-                }).then(function (revisions) {
-                    if (revisions.length <= 0) {
-                        // if no revision available
-                        Revision.create({
-                            noteId: note.id,
-                            lastContent: note.content,
-                            length: note.content.length,
-                            authorship: note.authorship
-                        }).then(function (revision) {
-                            Revision.finishSaveNoteRevision(note, revision, callback);
-                        }).catch(function (err) {
-                            return callback(err, null);
-                        });
-                    } else {
-                        var latestRevision = revisions[0];
-                        var lastContent = latestRevision.content || latestRevision.lastContent;
-                        var content = note.content;
-                        sendDmpWorker({
-                            msg: 'create patch',
-                            lastDoc: lastContent,
-                            currDoc: content,
-                        }, function (err, patch) {
-                            if (err) logger.error('save note revision error', err);
-                            if (!patch) {
-                                // if patch is empty (means no difference) then just update the latest revision updated time 
-                                latestRevision.changed('updatedAt', true); 
-                                latestRevision.update({
-                                    updatedAt: Date.now()
-                                }).then(function (revision) {
-                                    Revision.finishSaveNoteRevision(note, revision, callback);
-                                }).catch(function (err) {
-                                    return callback(err, null);
-                                });
-                            } else {
-                                Revision.create({
-                                    noteId: note.id,
-                                    patch: patch,
-                                    content: note.content,
-                                    length: note.content.length,
-                                    authorship: note.authorship
-                                }).then(function (revision) {
-                                    // clear last revision content to reduce db size
-                                    latestRevision.update({
-                                        content: null
-                                    }).then(function () {
-                                        Revision.finishSaveNoteRevision(note, revision, callback);
-                                    }).catch(function (err) {
-                                        return callback(err, null);
-                                    });
-                                }).catch(function (err) {
-                                    return callback(err, null);
-                                });
-                            }
-                        });
-                    }
-                }).catch(function (err) {
-                    return callback(err, null);
-                });
-            },
-            finishSaveNoteRevision: function (note, revision, callback) {
-                note.update({
-                    savedAt: revision.updatedAt
-                }).then(function () {
-                    return callback(null, revision);
-                }).catch(function (err) {
-                    return callback(err, null);
-                });
-            }
-        }
-    });
+                  return callback(err, null)
+                })
+              }
+            })
+          }
+        }).catch(function (err) {
+          return callback(err, null)
+        })
+      },
+      finishSaveNoteRevision: function (note, revision, callback) {
+        note.update({
+          savedAt: revision.updatedAt
+        }).then(function () {
+          return callback(null, revision)
+        }).catch(function (err) {
+          return callback(err, null)
+        })
+      }
+    }
+  })
 
-    return Revision;
-};
\ No newline at end of file
+  return Revision
+}
diff --git a/lib/models/temp.js b/lib/models/temp.js
index 6eeff153..e770bb3a 100644
--- a/lib/models/temp.js
+++ b/lib/models/temp.js
@@ -1,19 +1,17 @@
-"use strict";
-
-//external modules
-var shortId = require('shortid');
+// external modules
+var shortId = require('shortid')
 
 module.exports = function (sequelize, DataTypes) {
-    var Temp = sequelize.define("Temp", {
-        id: {
-            type: DataTypes.STRING,
-            primaryKey: true,
-            defaultValue: shortId.generate
-        },
-        data: {
-            type: DataTypes.TEXT
-        }
-    });
-    
-    return Temp;
-};
\ No newline at end of file
+  var Temp = sequelize.define('Temp', {
+    id: {
+      type: DataTypes.STRING,
+      primaryKey: true,
+      defaultValue: shortId.generate
+    },
+    data: {
+      type: DataTypes.TEXT
+    }
+  })
+
+  return Temp
+}
diff --git a/lib/models/user.js b/lib/models/user.js
index dd93bf78..f7e533b7 100644
--- a/lib/models/user.js
+++ b/lib/models/user.js
@@ -1,149 +1,147 @@
-"use strict";
-
 // external modules
-var md5 = require("blueimp-md5");
-var Sequelize = require("sequelize");
-var scrypt = require('scrypt');
+var md5 = require('blueimp-md5')
+var Sequelize = require('sequelize')
+var scrypt = require('scrypt')
 
 // core
-var logger = require("../logger.js");
-var letterAvatars = require('../letter-avatars.js');
+var logger = require('../logger.js')
+var letterAvatars = require('../letter-avatars.js')
 
 module.exports = function (sequelize, DataTypes) {
-    var User = sequelize.define("User", {
-        id: {
-            type: DataTypes.UUID,
-            primaryKey: true,
-            defaultValue: Sequelize.UUIDV4
-        },
-        profileid: {
-            type: DataTypes.STRING,
-            unique: true
-        },
-        profile: {
-            type: DataTypes.TEXT
-        },
-        history: {
-            type: DataTypes.TEXT
-        },
-        accessToken: {
-            type: DataTypes.STRING
-        },
-        refreshToken: {
-            type: DataTypes.STRING
-        },
-        email: {
-            type: Sequelize.TEXT, 
-            validate: {
-                isEmail: true
-            }
-        },
-        password: {
-            type: Sequelize.TEXT,
-            set: function(value) {
-                var hash = scrypt.kdfSync(value, scrypt.paramsSync(0.1)).toString("hex");
-                this.setDataValue('password', hash);
-            }
+  var User = sequelize.define('User', {
+    id: {
+      type: DataTypes.UUID,
+      primaryKey: true,
+      defaultValue: Sequelize.UUIDV4
+    },
+    profileid: {
+      type: DataTypes.STRING,
+      unique: true
+    },
+    profile: {
+      type: DataTypes.TEXT
+    },
+    history: {
+      type: DataTypes.TEXT
+    },
+    accessToken: {
+      type: DataTypes.STRING
+    },
+    refreshToken: {
+      type: DataTypes.STRING
+    },
+    email: {
+      type: Sequelize.TEXT,
+      validate: {
+        isEmail: true
+      }
+    },
+    password: {
+      type: Sequelize.TEXT,
+      set: function (value) {
+        var hash = scrypt.kdfSync(value, scrypt.paramsSync(0.1)).toString('hex')
+        this.setDataValue('password', hash)
+      }
+    }
+  }, {
+    instanceMethods: {
+      verifyPassword: function (attempt) {
+        if (scrypt.verifyKdfSync(new Buffer(this.password, 'hex'), attempt)) {
+          return this
+        } else {
+          return false
         }
-    }, {
-        instanceMethods: {
-            verifyPassword: function(attempt) {
-                if (scrypt.verifyKdfSync(new Buffer(this.password, "hex"), attempt)) {
-                    return this;
-                } else {
-                    return false;
-                }
-            }
-        },
-        classMethods: {
-            associate: function (models) {
-                User.hasMany(models.Note, {
-                    foreignKey: "ownerId",
-                    constraints: false
-                });
-                User.hasMany(models.Note, {
-                    foreignKey: "lastchangeuserId",
-                    constraints: false
-                });
-            },
-            getProfile: function (user) {
-                return user.profile ? User.parseProfile(user.profile) : (user.email ? User.parseProfileByEmail(user.email) : null);
-            },
-            parseProfile: function (profile) {
-                try {
-                    var profile = JSON.parse(profile);
-                } catch (err) {
-                    logger.error(err);
-                    profile = null;
-                }
-                if (profile) {
-                    profile = {
-                        name: profile.displayName || profile.username,
-                        photo: User.parsePhotoByProfile(profile),
-                        biggerphoto: User.parsePhotoByProfile(profile, true)
-                    }
-                }
-                return profile;
-            },
-            parsePhotoByProfile: function (profile, bigger) {
-                var photo = null;
-                switch (profile.provider) {
-                    case "facebook":
-                        photo = 'https://graph.facebook.com/' + profile.id + '/picture';
-                        if (bigger) photo += '?width=400';
-                        else photo += '?width=96';
-                        break;
-                    case "twitter":
-                        photo = 'https://twitter.com/' + profile.username + '/profile_image';
-                        if (bigger) photo += '?size=original';
-                        else photo += '?size=bigger';
-                        break;
-                    case "github":
-                        photo = 'https://avatars.githubusercontent.com/u/' + profile.id;
-                        if (bigger) photo += '?s=400';
-                        else photo += '?s=96';
-                        break;
-                    case "gitlab":
-                        photo = profile.avatarUrl;
-                        if (bigger) photo = photo.replace(/(\?s=)\d*$/i, '$1400');
-                        else photo = photo.replace(/(\?s=)\d*$/i, '$196');
-                        break;
-                    case "dropbox":
-                        //no image api provided, use gravatar
-                        photo = 'https://www.gravatar.com/avatar/' + md5(profile.emails[0].value);
-                        if (bigger) photo += '?s=400';
-                        else photo += '?s=96';
-                        break;
-                    case "google":
-                        photo = profile.photos[0].value;
-                        if (bigger) photo = photo.replace(/(\?sz=)\d*$/i, '$1400');
-                        else photo = photo.replace(/(\?sz=)\d*$/i, '$196');
-                        break;
-                    case "ldap":
-                        //no image api provided,
-                        //use gravatar if email exists,
-                        //otherwise generate a letter avatar
-                        if (profile.emails[0]) {
-                            photo = 'https://www.gravatar.com/avatar/' + md5(profile.emails[0]);
-                            if (bigger) photo += '?s=400';
-                            else photo += '?s=96';
-                        } else {
-                            photo = letterAvatars(profile.username);
-                        }
-                        break;
-                }
-                return photo;
-            },
-            parseProfileByEmail: function (email) {
-                var photoUrl = 'https://www.gravatar.com/avatar/' + md5(email);
-                return {
-                    name: email.substring(0, email.lastIndexOf("@")),
-                    photo: photoUrl += '?s=96',
-                    biggerphoto: photoUrl += '?s=400'
-                };
+      }
+    },
+    classMethods: {
+      associate: function (models) {
+        User.hasMany(models.Note, {
+          foreignKey: 'ownerId',
+          constraints: false
+        })
+        User.hasMany(models.Note, {
+          foreignKey: 'lastchangeuserId',
+          constraints: false
+        })
+      },
+      getProfile: function (user) {
+        return user.profile ? User.parseProfile(user.profile) : (user.email ? User.parseProfileByEmail(user.email) : null)
+      },
+      parseProfile: function (profile) {
+        try {
+          profile = JSON.parse(profile)
+        } catch (err) {
+          logger.error(err)
+          profile = null
+        }
+        if (profile) {
+          profile = {
+            name: profile.displayName || profile.username,
+            photo: User.parsePhotoByProfile(profile),
+            biggerphoto: User.parsePhotoByProfile(profile, true)
+          }
+        }
+        return profile
+      },
+      parsePhotoByProfile: function (profile, bigger) {
+        var photo = null
+        switch (profile.provider) {
+          case 'facebook':
+            photo = 'https://graph.facebook.com/' + profile.id + '/picture'
+            if (bigger) photo += '?width=400'
+            else photo += '?width=96'
+            break
+          case 'twitter':
+            photo = 'https://twitter.com/' + profile.username + '/profile_image'
+            if (bigger) photo += '?size=original'
+            else photo += '?size=bigger'
+            break
+          case 'github':
+            photo = 'https://avatars.githubusercontent.com/u/' + profile.id
+            if (bigger) photo += '?s=400'
+            else photo += '?s=96'
+            break
+          case 'gitlab':
+            photo = profile.avatarUrl
+            if (bigger) photo = photo.replace(/(\?s=)\d*$/i, '$1400')
+            else photo = photo.replace(/(\?s=)\d*$/i, '$196')
+            break
+          case 'dropbox':
+            // no image api provided, use gravatar
+            photo = 'https://www.gravatar.com/avatar/' + md5(profile.emails[0].value)
+            if (bigger) photo += '?s=400'
+            else photo += '?s=96'
+            break
+          case 'google':
+            photo = profile.photos[0].value
+            if (bigger) photo = photo.replace(/(\?sz=)\d*$/i, '$1400')
+            else photo = photo.replace(/(\?sz=)\d*$/i, '$196')
+            break
+          case 'ldap':
+            // no image api provided,
+            // use gravatar if email exists,
+            // otherwise generate a letter avatar
+            if (profile.emails[0]) {
+              photo = 'https://www.gravatar.com/avatar/' + md5(profile.emails[0])
+              if (bigger) photo += '?s=400'
+              else photo += '?s=96'
+            } else {
+              photo = letterAvatars(profile.username)
             }
+            break
+        }
+        return photo
+      },
+      parseProfileByEmail: function (email) {
+        var photoUrl = 'https://www.gravatar.com/avatar/' + md5(email)
+        return {
+          name: email.substring(0, email.lastIndexOf('@')),
+          photo: photoUrl + '?s=96',
+          biggerphoto: photoUrl + '?s=400'
         }
-    });
+      }
+    }
+  })
 
-    return User;
-};
\ No newline at end of file
+  return User
+}