diff --git a/chrome/content/zotero/locateMenu.js b/chrome/content/zotero/locateMenu.js
index a46fa5afd1..13df37cd27 100644
--- a/chrome/content/zotero/locateMenu.js
+++ b/chrome/content/zotero/locateMenu.js
@@ -544,7 +544,7 @@ var Zotero_LocateMenu = new function() {
 		this.useExternalViewer = true;
 		
 		this.canHandleItem = function (item) {
-			return _getBestFile(item).then(function (item) !!item);
+			return _getBestFile(item).then(item => !!item);
 		}
 		
 		this.handleItems = Zotero.Promise.coroutine(function* (items, event) {
@@ -573,7 +573,7 @@ var Zotero_LocateMenu = new function() {
 	 */
 	ViewOptions._libraryLookup = new function() {
 		this.icon = "chrome://zotero/skin/locate-library-lookup.png";
-		this.canHandleItem = function (item) Zotero.Promise.resolve(item.isRegularItem());
+		this.canHandleItem = function (item) { return Zotero.Promise.resolve(item.isRegularItem()); };
 		this.handleItems = Zotero.Promise.method(function (items, event) {
 			var urls = [];
 			for (let item of items) {
diff --git a/chrome/content/zotero/xpcom/data/cachedTypes.js b/chrome/content/zotero/xpcom/data/cachedTypes.js
index 620a2b0b02..e34b6089f6 100644
--- a/chrome/content/zotero/xpcom/data/cachedTypes.js
+++ b/chrome/content/zotero/xpcom/data/cachedTypes.js
@@ -371,9 +371,9 @@ Zotero.ItemTypes = new function() {
 			}
 			if (params.length) {
 				sql += 'OR id IN '
-						+ '(' + params.map(function () '?').join() + ') '
+						+ '(' + params.map(() => '?').join() + ') '
 						+ 'ORDER BY id NOT IN '
-						+ '(' + params.map(function () '?').join() + ') ';
+						+ '(' + params.map(() => '?').join() + ') ';
 				params = params.concat(params);
 			}
 			else {
diff --git a/chrome/content/zotero/xpcom/data/collection.js b/chrome/content/zotero/xpcom/data/collection.js
index b7e998fdb5..c210e4aed6 100644
--- a/chrome/content/zotero/xpcom/data/collection.js
+++ b/chrome/content/zotero/xpcom/data/collection.js
@@ -45,32 +45,32 @@ Zotero.Collection.prototype._dataTypes = Zotero.Collection._super.prototype._dat
 ]);
 
 Zotero.defineProperty(Zotero.Collection.prototype, 'ChildObjects', {
-	get: function() Zotero.Items
+	get: function() { return Zotero.Items; }
 });
 
 Zotero.defineProperty(Zotero.Collection.prototype, 'id', {
-	get: function() this._get('id'),
-	set: function(val) this._set('id', val)
+	get: function() { return this._get('id'); },
+	set: function(val) { return this._set('id', val); }
 });
 Zotero.defineProperty(Zotero.Collection.prototype, 'libraryID', {
-	get: function() this._get('libraryID'),
-	set: function(val) this._set('libraryID', val)
+	get: function() { return this._get('libraryID'); },
+	set: function(val) { return this._set('libraryID', val); }
 });
 Zotero.defineProperty(Zotero.Collection.prototype, 'key', {
-	get: function() this._get('key'),
-	set: function(val) this._set('key', val)
+	get: function() { return this._get('key'); },
+	set: function(val) { return this._set('key', val); }
 });
 Zotero.defineProperty(Zotero.Collection.prototype, 'name', {
-	get: function() this._get('name'),
-	set: function(val) this._set('name', val)
+	get: function() { return this._get('name'); },
+	set: function(val) { return this._set('name', val); }
 });
 Zotero.defineProperty(Zotero.Collection.prototype, 'version', {
-	get: function() this._get('version'),
-	set: function(val) this._set('version', val)
+	get: function() { return this._get('version'); },
+	set: function(val) { return this._set('version', val); }
 });
 Zotero.defineProperty(Zotero.Collection.prototype, 'synced', {
-	get: function() this._get('synced'),
-	set: function(val) this._set('synced', val)
+	get: function() { return this._get('synced'); },
+	set: function(val) { return this._set('synced', val); }
 });
 Zotero.defineProperty(Zotero.Collection.prototype, 'parent', {
 	get: function() {
@@ -290,14 +290,14 @@ Zotero.Collection.prototype._saveData = Zotero.Promise.coroutine(function* (env)
 		env.sqlColumns.unshift('collectionID');
 		env.sqlValues.unshift(collectionID ? { int: collectionID } : null);
 		
-		let placeholders = env.sqlColumns.map(function () '?').join();
+		let placeholders = env.sqlColumns.map(() => '?').join();
 		let sql = "INSERT INTO collections (" + env.sqlColumns.join(', ') + ") "
 			+ "VALUES (" + placeholders + ")";
 		yield Zotero.DB.queryAsync(sql, env.sqlValues);
 	}
 	else {
 		let sql = 'UPDATE collections SET '
-			+ env.sqlColumns.map(function (x) x + '=?').join(', ') + ' WHERE collectionID=?';
+			+ env.sqlColumns.map(x => x + '=?').join(', ') + ' WHERE collectionID=?';
 		env.sqlValues.push(collectionID ? { int: collectionID } : null);
 		yield Zotero.DB.queryAsync(sql, env.sqlValues);
 	}
@@ -604,7 +604,7 @@ Zotero.Collection.prototype._eraseData = Zotero.Promise.coroutine(function* (env
 		}
 	}
 	
-	var placeholders = collections.map(function () '?').join();
+	var placeholders = collections.map(() => '?').join();
 	
 	// Remove item associations for all descendent collections
 	yield Zotero.DB.queryAsync('DELETE FROM collectionItems WHERE collectionID IN '
diff --git a/chrome/content/zotero/xpcom/data/collections.js b/chrome/content/zotero/xpcom/data/collections.js
index ff6566fb13..b43a3ae87e 100644
--- a/chrome/content/zotero/xpcom/data/collections.js
+++ b/chrome/content/zotero/xpcom/data/collections.js
@@ -104,7 +104,7 @@ Zotero.Collections = function() {
 		}
 		
 		// Do proper collation sort
-		children.sort(function (a, b) Zotero.localeCompare(a.name, b.name));
+		children.sort((a, b) => Zotero.localeCompare(a.name, b.name));
 		
 		if (!recursive) return children;
 		
diff --git a/chrome/content/zotero/xpcom/data/dataObject.js b/chrome/content/zotero/xpcom/data/dataObject.js
index 9c99eef61a..35aedb5a36 100644
--- a/chrome/content/zotero/xpcom/data/dataObject.js
+++ b/chrome/content/zotero/xpcom/data/dataObject.js
@@ -66,13 +66,13 @@ Zotero.DataObject.prototype._objectType = 'dataObject';
 Zotero.DataObject.prototype._dataTypes = ['primaryData'];
 
 Zotero.defineProperty(Zotero.DataObject.prototype, 'objectType', {
-	get: function() this._objectType
+	get: function() { return this._objectType; }
 });
 Zotero.defineProperty(Zotero.DataObject.prototype, 'id', {
-	get: function() this._id
+	get: function() { return this._id; }
 });
 Zotero.defineProperty(Zotero.DataObject.prototype, 'libraryID', {
-	get: function() this._libraryID
+	get: function() { return this._libraryID; }
 });
 Zotero.defineProperty(Zotero.DataObject.prototype, 'library', {
 	get: function () {
@@ -80,18 +80,18 @@ Zotero.defineProperty(Zotero.DataObject.prototype, 'library', {
 	}
 });
 Zotero.defineProperty(Zotero.DataObject.prototype, 'key', {
-	get: function() this._key
+	get: function() { return this._key; }
 });
 Zotero.defineProperty(Zotero.DataObject.prototype, 'libraryKey', {
-	get: function() this._libraryID + "/" + this._key
+	get: function() { return this._libraryID + "/" + this._key; }
 });
 Zotero.defineProperty(Zotero.DataObject.prototype, 'parentKey', {
-	get: function () this._getParentKey(),
-	set: function(v) this._setParentKey(v)
+	get: function () { return this._getParentKey(); },
+	set: function(v) { return this._setParentKey(v); }
 });
 Zotero.defineProperty(Zotero.DataObject.prototype, 'parentID', {
-	get: function() this._getParentID(),
-	set: function(v) this._setParentID(v)
+	get: function() { return this._getParentID(); },
+	set: function(v) { return this._setParentID(v); }
 });
 
 Zotero.defineProperty(Zotero.DataObject.prototype, '_canHaveParent', {
@@ -99,7 +99,7 @@ Zotero.defineProperty(Zotero.DataObject.prototype, '_canHaveParent', {
 });
 
 Zotero.defineProperty(Zotero.DataObject.prototype, 'ObjectsClass', {
-	get: function() this._ObjectsClass
+	get: function() { return this._ObjectsClass; }
 });
 
 
diff --git a/chrome/content/zotero/xpcom/data/dataObjects.js b/chrome/content/zotero/xpcom/data/dataObjects.js
index 7426e453bf..1b399ca9de 100644
--- a/chrome/content/zotero/xpcom/data/dataObjects.js
+++ b/chrome/content/zotero/xpcom/data/dataObjects.js
@@ -62,18 +62,18 @@ Zotero.DataObjects.prototype._ZDO_idOnly = false;
 
 // Public properties
 Zotero.defineProperty(Zotero.DataObjects.prototype, 'idColumn', {
-	get: function() this._ZDO_id
+	get: function() { return this._ZDO_id; }
 });
 Zotero.defineProperty(Zotero.DataObjects.prototype, 'table', {
-	get: function() this._ZDO_table
+	get: function() { return this._ZDO_table; }
 });
 
 Zotero.defineProperty(Zotero.DataObjects.prototype, 'relationsTable', {
-	get: function() this._ZDO_object + 'Relations'
+	get: function() { return this._ZDO_object + 'Relations'; }
 });
 
 Zotero.defineProperty(Zotero.DataObjects.prototype, 'primaryFields', {
-	get: function () Object.keys(this._primaryDataSQLParts)
+	get: function () { return Object.keys(this._primaryDataSQLParts); }
 }, {lazy: true});
 
 Zotero.defineProperty(Zotero.DataObjects.prototype, "_primaryDataSQLWhere", {
@@ -81,7 +81,7 @@ Zotero.defineProperty(Zotero.DataObjects.prototype, "_primaryDataSQLWhere", {
 });
 
 Zotero.defineProperty(Zotero.DataObjects.prototype, 'primaryDataSQLFrom', {
-	get: function() " " + this._primaryDataSQLFrom + " " + this._primaryDataSQLWhere
+	get: function() { return " " + this._primaryDataSQLFrom + " " + this._primaryDataSQLWhere; }
 }, {lateInit: true});
 
 Zotero.DataObjects.prototype.init = function() {
diff --git a/chrome/content/zotero/xpcom/data/feed.js b/chrome/content/zotero/xpcom/data/feed.js
index 77b6bbf1cd..21ff215716 100644
--- a/chrome/content/zotero/xpcom/data/feed.js
+++ b/chrome/content/zotero/xpcom/data/feed.js
@@ -51,13 +51,13 @@ Zotero.Feed = function(params = {}) {
 	// Feeds are not editable by the user. Remove the setter
 	this.editable = false;
 	Zotero.defineProperty(this, 'editable', {
-		get: function() this._get('_libraryEditable')
+		get: function() { return this._get('_libraryEditable'); }
 	});
 
 	// Feeds are not filesEditable by the user. Remove the setter
 	this.filesEditable = false;
 	Zotero.defineProperty(this, 'filesEditable', {
-		get: function() this._get('_libraryFilesEditable')
+		get: function() { return this._get('_libraryFilesEditable'); }
 	});
 	
 	Zotero.Utilities.assignProps(this, params, 
@@ -115,10 +115,10 @@ Zotero.defineProperty(Zotero.Feed.prototype, 'libraryTypes', {
 	value: Object.freeze(Zotero.Feed._super.prototype.libraryTypes.concat(['feed']))
 });
 Zotero.defineProperty(Zotero.Feed.prototype, 'unreadCount', {
-	get: function() this._feedUnreadCount
+	get: function() { return this._feedUnreadCount; }
 });
 Zotero.defineProperty(Zotero.Feed.prototype, 'updating', {
-	get: function() !!this._updating,
+	get: function() { return !!this._updating; }
 });
 
 (function() {
@@ -128,8 +128,8 @@ for (let i=0; i<accessors.length; i++) {
 	let name = accessors[i];
 	let prop = Zotero.Feed._colToProp(name);
 	Zotero.defineProperty(Zotero.Feed.prototype, name, {
-		get: function() this._get(prop),
-		set: function(v) this._set(prop, v)
+		get: function() { return this._get(prop); },
+		set: function(v) { return this._set(prop, v); }
 	})
 }
 let getters = ['lastCheck', 'lastUpdate', 'lastCheckError'];
@@ -137,7 +137,7 @@ for (let i=0; i<getters.length; i++) {
 	let name = getters[i];
 	let prop = Zotero.Feed._colToProp(name);
 	Zotero.defineProperty(Zotero.Feed.prototype, name, {
-		get: function() this._get(prop),
+		get: function() { return this._get(prop); }
 	})
 }
 })()
diff --git a/chrome/content/zotero/xpcom/data/feedItem.js b/chrome/content/zotero/xpcom/data/feedItem.js
index 1200f91be3..71644d938c 100644
--- a/chrome/content/zotero/xpcom/data/feedItem.js
+++ b/chrome/content/zotero/xpcom/data/feedItem.js
@@ -46,7 +46,7 @@ Zotero.defineProperty(Zotero.FeedItem.prototype, 'isFeedItem', {
 });
 
 Zotero.defineProperty(Zotero.FeedItem.prototype, 'guid', {
-	get: function() this._feedItemGUID,
+	get: function() { return this._feedItemGUID; },
 	set: function(val) {
 		if (this.id) throw new Error('Cannot set GUID after item ID is already set');
 		if (typeof val != 'string') throw new Error('GUID must be a non-empty string');
diff --git a/chrome/content/zotero/xpcom/data/group.js b/chrome/content/zotero/xpcom/data/group.js
index 99f92d5f5d..f38d0f269b 100644
--- a/chrome/content/zotero/xpcom/data/group.js
+++ b/chrome/content/zotero/xpcom/data/group.js
@@ -58,7 +58,7 @@ Zotero.Group._colToProp = function(c) {
 
 Zotero.defineProperty(Zotero.Group, '_rowSQLSelect', {
 	value: Zotero.Library._rowSQLSelect + ", G.groupID, "
-		+ Zotero.Group._dbColumns.map(function(c) "G." + c + " AS " + Zotero.Group._colToProp(c)).join(", ")
+		+ Zotero.Group._dbColumns.map(c => "G." + c + " AS " + Zotero.Group._colToProp(c)).join(", ")
 });
 
 Zotero.defineProperty(Zotero.Group, '_rowSQL', {
@@ -77,13 +77,13 @@ Zotero.defineProperty(Zotero.Group.prototype, 'libraryTypes', {
 });
 
 Zotero.defineProperty(Zotero.Group.prototype, 'groupID', {
-	get: function() this._groupID,
-	set: function(v) this._groupID = v
+	get: function() { return this._groupID; },
+	set: function(v) { return this._groupID = v; }
 });
 
 Zotero.defineProperty(Zotero.Group.prototype, 'id', {
-	get: function() this.groupID,
-	set: function(v) this.groupID = v
+	get: function() { return this.groupID; },
+	set: function(v) { return this.groupID = v; }
 });
 
 // Create accessors
@@ -93,8 +93,8 @@ for (let i=0; i<accessors.length; i++) {
 	let name = accessors[i];
 	let prop = Zotero.Group._colToProp(name);
 	Zotero.defineProperty(Zotero.Group.prototype, name, {
-		get: function() this._get(prop),
-		set: function(v) this._set(prop, v)
+		get: function() { return this._get(prop); },
+		set: function(v) { return this._set(prop, v); }
 	})
 }
 })();
@@ -201,7 +201,7 @@ Zotero.Group.prototype._saveData = Zotero.Promise.coroutine(function* (env) {
 		Zotero.Notifier.queue('add', 'group', this.groupID);
 	}
 	else if (changedCols.length) {
-		let sql = "UPDATE groups SET " + changedCols.map(function (v) v + '=?').join(', ')
+		let sql = "UPDATE groups SET " + changedCols.map(v => v + '=?').join(', ')
 			+ " WHERE groupID=?";
 		params.push(this.groupID);
 		yield Zotero.DB.queryAsync(sql, params);
diff --git a/chrome/content/zotero/xpcom/data/item.js b/chrome/content/zotero/xpcom/data/item.js
index 56fe5dbea4..cc9e1d802c 100644
--- a/chrome/content/zotero/xpcom/data/item.js
+++ b/chrome/content/zotero/xpcom/data/item.js
@@ -89,7 +89,7 @@ Zotero.extendClass(Zotero.DataObject, Zotero.Item);
 
 Zotero.Item.prototype._objectType = 'item';
 Zotero.defineProperty(Zotero.Item.prototype, 'ContainerObjectsClass', {
-	get: function() Zotero.Collections
+	get: function() { return Zotero.Collections; }
 });
 
 Zotero.Item.prototype._dataTypes = Zotero.Item._super.prototype._dataTypes.concat([
@@ -104,8 +104,8 @@ Zotero.Item.prototype._dataTypes = Zotero.Item._super.prototype._dataTypes.conca
 ]);
 
 Zotero.defineProperty(Zotero.Item.prototype, 'id', {
-	get: function() this._id,
-	set: function(val) this.setField('id', val)
+	get: function() { return this._id; },
+	set: function(val) { return this.setField('id', val); }
 });
 Zotero.defineProperty(Zotero.Item.prototype, 'itemID', {
 	get: function() {
@@ -114,52 +114,52 @@ Zotero.defineProperty(Zotero.Item.prototype, 'itemID', {
 	}
 });
 Zotero.defineProperty(Zotero.Item.prototype, 'libraryID', {
-	get: function() this._libraryID,
-	set: function(val) this.setField('libraryID', val)
+	get: function() { return this._libraryID; },
+	set: function(val) { return this.setField('libraryID', val); }
 });
 Zotero.defineProperty(Zotero.Item.prototype, 'key', {
-	get: function() this._key,
-	set: function(val) this.setField('key', val)
+	get: function() { return this._key; },
+	set: function(val) { return this.setField('key', val); }
 });
 Zotero.defineProperty(Zotero.Item.prototype, 'itemTypeID', {
-	get: function() this._itemTypeID
+	get: function() { return this._itemTypeID; }
 });
 Zotero.defineProperty(Zotero.Item.prototype, 'dateAdded', {
-	get: function() this._dateAdded,
-	set: function(val) this.setField('dateAdded', val)
+	get: function() { return this._dateAdded; },
+	set: function(val) { return this.setField('dateAdded', val); }
 });
 Zotero.defineProperty(Zotero.Item.prototype, 'dateModified', {
-	get: function() this._dateModified,
-	set: function(val) this.setField('dateModified', val)
+	get: function() { return this._dateModified; },
+	set: function(val) { return this.setField('dateModified', val); }
 });
 Zotero.defineProperty(Zotero.Item.prototype, 'version', {
-	get: function() this._version,
-	set: function(val) this.setField('version', val)
+	get: function() { return this._version; },
+	set: function(val) { return this.setField('version', val); }
 });
 Zotero.defineProperty(Zotero.Item.prototype, 'synced', {
-	get: function() this._synced,
-	set: function(val) this.setField('synced', val)
+	get: function() { return this._synced; },
+	set: function(val) { return this.setField('synced', val); }
 });
 
 // .parentKey and .parentID defined in dataObject.js, but create aliases
 Zotero.defineProperty(Zotero.Item.prototype, 'parentItemID', {
-	get: function() this.parentID,
-	set: function(val) this.parentID = val
+	get: function() { return this.parentID; },
+	set: function(val) { return this.parentID = val; }
 });
 Zotero.defineProperty(Zotero.Item.prototype, 'parentItemKey', {
-	get: function() this.parentKey,
-	set: function(val) this.parentKey = val
+	get: function() { return this.parentKey; },
+	set: function(val) { return this.parentKey = val; }
 });
 
 
 Zotero.defineProperty(Zotero.Item.prototype, 'firstCreator', {
-	get: function() this._firstCreator
+	get: function() { return this._firstCreator; }
 });
 Zotero.defineProperty(Zotero.Item.prototype, 'sortCreator', {
-	get: function() this._sortCreator
+	get: function() { return this._sortCreator; }
 });
 Zotero.defineProperty(Zotero.Item.prototype, 'relatedItems', {
-	get: function() this._getRelatedItems()
+	get: function() { return this._getRelatedItems(); }
 });
 
 Zotero.defineProperty(Zotero.Item.prototype, 'treeViewID', {
@@ -1023,7 +1023,7 @@ Zotero.Item.prototype.getCreators = function () {
  */
 Zotero.Item.prototype.getCreatorsJSON = function () {
 	this._requireData('creators');
-	return this._creators.map(function (data) Zotero.Creators.internalToJSON(data));
+	return this._creators.map(data => Zotero.Creators.internalToJSON(data));
 }
 
 
@@ -1274,7 +1274,7 @@ Zotero.Item.prototype._saveData = Zotero.Promise.coroutine(function* (env) {
 		env.sqlValues.unshift(parseInt(itemID));
 		
 		let sql = "INSERT INTO items (" + env.sqlColumns.join(", ") + ") "
-			+ "VALUES (" + env.sqlValues.map(function () "?").join() + ")";
+			+ "VALUES (" + env.sqlValues.map(() => "?").join() + ")";
 		yield Zotero.DB.queryAsync(sql, env.sqlValues);
 		
 		if (!env.options.skipNotifier) {
@@ -1328,7 +1328,7 @@ Zotero.Item.prototype._saveData = Zotero.Promise.coroutine(function* (env) {
 		// Delete blank fields
 		if (del.length) {
 			sql = 'DELETE from itemData WHERE itemID=? AND '
-				+ 'fieldID IN (' + del.map(function () '?').join() + ')';
+				+ 'fieldID IN (' + del.map(() => '?').join() + ')';
 			yield Zotero.DB.queryAsync(sql, [itemID].concat(del));
 		}
 	}
@@ -2040,7 +2040,7 @@ Zotero.Item.prototype.getNotes = function(includeTrashed) {
 	var rows = this._notes.rows.concat();
 	// Remove trashed items if necessary
 	if (!includeTrashed) {
-		rows = rows.filter(function (row) !row.trashed);
+		rows = rows.filter(row => !row.trashed);
 	}
 	// Sort by title if necessary
 	if (!sortChronologically) {
@@ -3205,12 +3205,12 @@ Zotero.Item.prototype.getAttachments = function(includeTrashed) {
 	var rows = this._attachments.rows.concat();
 	// Remove trashed items if necessary
 	if (!includeTrashed) {
-		rows = rows.filter(function (row) !row.trashed);
+		rows = rows.filter(row => !row.trashed);
 	}
 	// Sort by title if necessary
 	if (!Zotero.Prefs.get('sortAttachmentsChronologically')) {
 		var collation = Zotero.getLocaleCollation();
-		rows.sort(function (a, b) collation.compareString(1, a.title, b.title));
+		rows.sort((a, b) => collation.compareString(1, a.title, b.title));
 	}
 	var ids = rows.map(row => row.itemID);
 	this._attachments[cacheKey] = ids;
@@ -3317,7 +3317,7 @@ Zotero.Item.prototype.getTags = function () {
  */
 Zotero.Item.prototype.hasTag = function (tagName) {
 	this._requireData('tags');
-	return this._tags.some(function (tagData) tagData.tag == tagName);
+	return this._tags.some(tagData => tagData.tag == tagName);
 }
 
 
@@ -3454,7 +3454,7 @@ Zotero.Item.prototype.replaceTag = function (oldTag, newTag) {
  */
 Zotero.Item.prototype.removeTag = function(tagName) {
 	this._requireData('tags');
-	var newTags = this._tags.filter(function (tagData) tagData.tag !== tagName);
+	var newTags = this._tags.filter(tagData => tagData.tag !== tagName);
 	if (newTags.length == this._tags.length) {
 		Zotero.debug('Cannot remove missing tag ' + tagName + ' from item ' + this.libraryKey);
 		return;
@@ -3658,7 +3658,7 @@ Zotero.Item.prototype.getImageSrcWithTags = Zotero.Promise.coroutine(function* (
 	colorData.sort(function (a, b) {
 		return a.position - b.position;
 	});
-	var colors = colorData.map(function (val) val.color);
+	var colors = colorData.map(val => val.color);
 	return Zotero.Tags.generateItemsListImage(colors, uri);
 });
 
diff --git a/chrome/content/zotero/xpcom/data/library.js b/chrome/content/zotero/xpcom/data/library.js
index d401168bc2..1e576c9787 100644
--- a/chrome/content/zotero/xpcom/data/library.js
+++ b/chrome/content/zotero/xpcom/data/library.js
@@ -79,7 +79,7 @@ Zotero.Library._colToProp = function(c) {
 
 // Select all columns in a unique manner, so we can JOIN tables with same column names (e.g. version)
 Zotero.defineProperty(Zotero.Library, '_rowSQLSelect', {
-	value: "L.libraryID, " + Zotero.Library._dbColumns.map(function(c) "L." + c + " AS " + Zotero.Library._colToProp(c)).join(", ")
+	value: "L.libraryID, " + Zotero.Library._dbColumns.map(c => "L." + c + " AS " + Zotero.Library._colToProp(c)).join(", ")
 		+ ", (SELECT COUNT(*)>0 FROM collections C WHERE C.libraryID=L.libraryID) AS hasCollections"
 		+ ", (SELECT COUNT(*)>0 FROM savedSearches S WHERE S.libraryID=L.libraryID) AS hasSearches"
 });
@@ -111,18 +111,18 @@ Zotero.defineProperty(Zotero.Library.prototype, 'fixedLibraries', {
 });
 
 Zotero.defineProperty(Zotero.Library.prototype, 'libraryID', {
-	get: function() this._libraryID,
-	set: function(id) { throw new Error("Cannot change library ID") }
+	get: function() { return this._libraryID; },
+	set: function(id) { throw new Error("Cannot change library ID"); }
 });
 
 Zotero.defineProperty(Zotero.Library.prototype, 'id', {
-	get: function() this.libraryID,
-	set: function(val) this.libraryID = val
+	get: function() { return this.libraryID; },
+	set: function(val) { return this.libraryID = val; }
 });
 
 Zotero.defineProperty(Zotero.Library.prototype, 'libraryType', {
-	get: function() this._get('_libraryType'),
-	set: function(v) this._set('_libraryType', v)
+	get: function() { return this._get('_libraryType'); },
+	set: function(v) { return this._set('_libraryType', v); }
 });
 
 /**
@@ -148,8 +148,8 @@ Zotero.defineProperty(Zotero.Library.prototype, 'libraryTypeID', {
 });
 
 Zotero.defineProperty(Zotero.Library.prototype, 'libraryVersion', {
-	get: function() this._get('_libraryVersion'),
-	set: function(v) this._set('_libraryVersion', v)
+	get: function() { return this._get('_libraryVersion'); },
+	set: function(v) { return this._set('_libraryVersion', v); }
 });
 
 
@@ -159,7 +159,7 @@ Zotero.defineProperty(Zotero.Library.prototype, 'syncable', {
 
 
 Zotero.defineProperty(Zotero.Library.prototype, 'lastSync', {
-	get: function() this._get('_libraryLastSync')
+	get: function() { return this._get('_libraryLastSync'); }
 });
 
 
@@ -199,8 +199,8 @@ Zotero.defineProperty(Zotero.Library.prototype, 'hasTrash', {
 	for (let i=0; i<accessors.length; i++) {
 		let prop = Zotero.Library._colToProp(accessors[i]);
 		Zotero.defineProperty(Zotero.Library.prototype, accessors[i], {
-			get: function() this._get(prop),
-			set: function(v) this._set(prop, v)
+			get: function() { return this._get(prop); },
+			set: function(v) { return this._set(prop, v); }
 		})
 	}
 })()
@@ -514,7 +514,7 @@ Zotero.Library.prototype._saveData = Zotero.Promise.coroutine(function* (env) {
 		this._libraryID = id;
 	} else if (changedCols.length) {
 		params.push(this.libraryID);
-		let sql = "UPDATE libraries SET " + changedCols.map(function(v) v + "=?").join(", ")
+		let sql = "UPDATE libraries SET " + changedCols.map(v => v + "=?").join(", ")
 			+ " WHERE libraryID=?";
 		yield Zotero.DB.queryAsync(sql, params);
 		
diff --git a/chrome/content/zotero/xpcom/data/notes.js b/chrome/content/zotero/xpcom/data/notes.js
index bc48ec6194..f2cda0d58e 100644
--- a/chrome/content/zotero/xpcom/data/notes.js
+++ b/chrome/content/zotero/xpcom/data/notes.js
@@ -28,9 +28,9 @@ Zotero.Notes = new function() {
 	this.noteToTitle = noteToTitle;
 	
 	this.__defineGetter__("MAX_TITLE_LENGTH", function() { return 120; });
-	this.__defineGetter__("defaultNote", function () '<div class="zotero-note znv1"></div>');
-	this.__defineGetter__("notePrefix", function () '<div class="zotero-note znv1">');
-	this.__defineGetter__("noteSuffix", function () '</div>');
+	this.__defineGetter__("defaultNote", function () { return '<div class="zotero-note znv1"></div>'; });
+	this.__defineGetter__("notePrefix", function () { return '<div class="zotero-note znv1">'; });
+	this.__defineGetter__("noteSuffix", function () { return '</div>'; });
 	
 	/**
 	* Return first line (or first MAX_LENGTH characters) of note content
diff --git a/chrome/content/zotero/xpcom/data/search.js b/chrome/content/zotero/xpcom/data/search.js
index 8da92927ac..91a28cb48a 100644
--- a/chrome/content/zotero/xpcom/data/search.js
+++ b/chrome/content/zotero/xpcom/data/search.js
@@ -62,31 +62,31 @@ Zotero.Search.prototype.setName = function(val) {
 }
 
 Zotero.defineProperty(Zotero.Search.prototype, 'id', {
-	get: function() this._get('id'),
-	set: function(val) this._set('id', val)
+	get: function() { return this._get('id'); },
+	set: function(val) { return this._set('id', val); }
 });
 Zotero.defineProperty(Zotero.Search.prototype, 'libraryID', {
-	get: function() this._get('libraryID'),
-	set: function(val) this._set('libraryID', val)
+	get: function() { return this._get('libraryID'); },
+	set: function(val) { return this._set('libraryID', val); }
 });
 Zotero.defineProperty(Zotero.Search.prototype, 'key', {
-	get: function() this._get('key'),
-	set: function(val) this._set('key', val)
+	get: function() { return this._get('key'); },
+	set: function(val) { return this._set('key', val); }
 });
 Zotero.defineProperty(Zotero.Search.prototype, 'name', {
-	get: function() this._get('name'),
-	set: function(val) this._set('name', val)
+	get: function() { return this._get('name'); },
+	set: function(val) { return this._set('name', val); }
 });
 Zotero.defineProperty(Zotero.Search.prototype, 'version', {
-	get: function() this._get('version'),
-	set: function(val) this._set('version', val)
+	get: function() { return this._get('version'); },
+	set: function(val) { return this._set('version', val); }
 });
 Zotero.defineProperty(Zotero.Search.prototype, 'synced', {
-	get: function() this._get('synced'),
-	set: function(val) this._set('synced', val)
+	get: function() { return this._get('synced'); },
+	set: function(val) { return this._set('synced', val); }
 });
 Zotero.defineProperty(Zotero.Search.prototype, 'conditions', {
-	get: function() this.getConditions()
+	get: function() { return this.getConditions(); }
 });
 Zotero.defineProperty(Zotero.Search.prototype, '_canHaveParent', {
 	value: false
@@ -175,14 +175,14 @@ Zotero.Search.prototype._saveData = Zotero.Promise.coroutine(function* (env) {
 		env.sqlColumns.unshift('savedSearchID');
 		env.sqlValues.unshift(searchID ? { int: searchID } : null);
 		
-		let placeholders = env.sqlColumns.map(function () '?').join();
+		let placeholders = env.sqlColumns.map(() => '?').join();
 		let sql = "INSERT INTO savedSearches (" + env.sqlColumns.join(', ') + ") "
 			+ "VALUES (" + placeholders + ")";
 		yield Zotero.DB.queryAsync(sql, env.sqlValues);
 	}
 	else {
 		let sql = 'UPDATE savedSearches SET '
-			+ env.sqlColumns.map(function (x) x + '=?').join(', ') + ' WHERE savedSearchID=?';
+			+ env.sqlColumns.map(x => x + '=?').join(', ') + ' WHERE savedSearchID=?';
 		env.sqlValues.push(searchID ? { int: searchID } : null);
 		yield Zotero.DB.queryAsync(sql, env.sqlValues);
 	}
@@ -634,7 +634,7 @@ Zotero.Search.prototype.search = Zotero.Promise.coroutine(function* (asTempTable
 		// (a separate fulltext word search filtered by fulltext content)
 		for (let condition of Object.values(this._conditions)){
 			if (condition['condition']=='fulltextContent'){
-				var fulltextWordIntersectionFilter = function (val, index, array) !!hash[val];
+				var fulltextWordIntersectionFilter = (val, index, array) => !!hash[val];
 				var fulltextWordIntersectionConditionFilter = function(val, index, array) {
 					return hash[val] ?
 						(condition.operator == 'contains') :
diff --git a/chrome/content/zotero/xpcom/data/tags.js b/chrome/content/zotero/xpcom/data/tags.js
index e0f04edbe7..e5b689bbfa 100644
--- a/chrome/content/zotero/xpcom/data/tags.js
+++ b/chrome/content/zotero/xpcom/data/tags.js
@@ -248,7 +248,7 @@ Zotero.Tags = new function() {
 				oldItemIDs,
 				Zotero.DB.MAX_BOUND_PARAMETERS - 2,
 				Zotero.Promise.coroutine(function* (chunk) {
-					let placeholders = chunk.map(function () '?').join(',');
+					let placeholders = chunk.map(() => '?').join(',');
 					
 					// This is ugly, but it's much faster than doing replaceTag() for each item
 					let sql = 'UPDATE OR REPLACE itemTags SET tagID=?, type=0 '
@@ -349,7 +349,7 @@ Zotero.Tags = new function() {
 				Zotero.Utilities.arrayUnique(oldItemIDs),
 				Zotero.DB.MAX_BOUND_PARAMETERS - 1,
 				Zotero.Promise.coroutine(function* (chunk) {
-					let placeholders = chunk.map(function () '?').join(',');
+					let placeholders = chunk.map(() => '?').join(',');
 					
 					sql = 'UPDATE items SET synced=0, clientDateModified=? '
 						+ 'WHERE itemID IN (' + placeholders + ')'
@@ -539,7 +539,7 @@ Zotero.Tags = new function() {
 				return;
 			}
 			
-			tagColors = tagColors.filter(function (val) val.name != name);
+			tagColors = tagColors.filter(val => val.name != name);
 		}
 		else {
 			// Get current position if present
@@ -620,7 +620,7 @@ Zotero.Tags = new function() {
 			var affectedItems = [];
 			
 			// Get all items linked to previous or current tag colors
-			var tagNames = tagColors.concat(previousTagColors).map(function (val) val.name);
+			var tagNames = tagColors.concat(previousTagColors).map(val => val.name);
 			tagNames = Zotero.Utilities.arrayUnique(tagNames);
 			if (tagNames.length) {
 				for (let i=0; i<tagNames.length; i++) {
diff --git a/chrome/content/zotero/xpcom/db.js b/chrome/content/zotero/xpcom/db.js
index 798f3d33c0..c9a2d4f6ff 100644
--- a/chrome/content/zotero/xpcom/db.js
+++ b/chrome/content/zotero/xpcom/db.js
@@ -375,7 +375,7 @@ Zotero.DBConnection.prototype.getNextName = Zotero.Promise.coroutine(function* (
 		+ " WHERE libraryID=? AND " + field + " LIKE ? ORDER BY " + field;
 	var params = [libraryID, name + "%"];
 	var suffixes = yield this.columnQueryAsync(sql, params);
-	suffixes.filter(function (x) x.match(/^( [0-9]+)?$/));
+	suffixes.filter(x => x.match(/^( [0-9]+)?$/));
 	
 	// If none found or first one has a suffix, use default name
 	if (!suffixes.length || suffixes[0]) {
@@ -841,15 +841,15 @@ Zotero.DBConnection.prototype.executeSQLFile = Zotero.Promise.coroutine(function
 		// Ugly hack to parse triggers with embedded semicolons
 		.replace(/;---/g, "TEMPSEMI")
 		.split("\n")
-		.filter(function (x) nonCommentRE.test(x))
-		.map(function (x) x.match(trailingCommentRE)[1])
+		.filter(x => nonCommentRE.test(x))
+		.map(x => x.match(trailingCommentRE)[1])
 		.join("");
 	if (sql.substr(-1) == ";") {
 		sql = sql.substr(0, sql.length - 1);
 	}
 	
 	var statements = sql.split(";")
-		.map(function (x) x.replace(/TEMPSEMI/g, ";"));
+		.map(x => x.replace(/TEMPSEMI/g, ";"));
 	
 	this.requireTransaction();
 	
diff --git a/chrome/content/zotero/xpcom/duplicates.js b/chrome/content/zotero/xpcom/duplicates.js
index e6e6786302..7784836980 100644
--- a/chrome/content/zotero/xpcom/duplicates.js
+++ b/chrome/content/zotero/xpcom/duplicates.js
@@ -36,8 +36,8 @@ Zotero.Duplicates = function (libraryID) {
 }
 
 
-Zotero.Duplicates.prototype.__defineGetter__('name', function () Zotero.getString('pane.collections.duplicate'));
-Zotero.Duplicates.prototype.__defineGetter__('libraryID', function () this._libraryID);
+Zotero.Duplicates.prototype.__defineGetter__('name', function () { return Zotero.getString('pane.collections.duplicate'); });
+Zotero.Duplicates.prototype.__defineGetter__('libraryID', function () { return this._libraryID; });
 
 /**
  * Get duplicates, populate a temporary table, and return a search based
@@ -251,7 +251,7 @@ Zotero.Duplicates.prototype._findDuplicates = Zotero.Promise.coroutine(function*
 				+ "JOIN itemData USING (itemID) "
 				+ "JOIN itemDataValues USING (valueID) "
 				+ "WHERE libraryID=? AND fieldID IN ("
-				+ dateFields.map(function () '?').join() + ") "
+				+ dateFields.map(() => '?').join() + ") "
 				+ "AND SUBSTR(value, 1, 4) != '0000' "
 				+ "AND itemID NOT IN (SELECT itemID FROM deletedItems) "
 				+ "ORDER BY value";
diff --git a/chrome/content/zotero/xpcom/http.js b/chrome/content/zotero/xpcom/http.js
index bc46e62785..f0bf022601 100644
--- a/chrome/content/zotero/xpcom/http.js
+++ b/chrome/content/zotero/xpcom/http.js
@@ -637,7 +637,7 @@ Zotero.HTTP = new function() {
 	 * through the error log and doing a fragile string comparison.
 	 */
 	_pacInstalled = function () {
-		return Zotero.getErrors(true).some(function (val) val.indexOf("PAC file installed") == 0)
+		return Zotero.getErrors(true).some(val => val.indexOf("PAC file installed") == 0)
 	}
 	
 	
diff --git a/chrome/content/zotero/xpcom/itemTreeView.js b/chrome/content/zotero/xpcom/itemTreeView.js
index 10cf893f64..9fbaa5fb20 100644
--- a/chrome/content/zotero/xpcom/itemTreeView.js
+++ b/chrome/content/zotero/xpcom/itemTreeView.js
@@ -480,7 +480,7 @@ Zotero.ItemTreeView.prototype.notify = Zotero.Promise.coroutine(function* (actio
 	// Clear item type icon and tag colors when a tag is added to or removed from an item
 	if (type == 'item-tag') {
 		// TODO: Only update if colored tag changed?
-		ids.map(function (val) val.split("-")[0]).forEach(function (val) {
+		ids.map(val => val.split("-")[0]).forEach(function (val) {
 			delete this._itemImages[val];
 		}.bind(this));
 		return;
@@ -1432,7 +1432,7 @@ Zotero.ItemTreeView.prototype.sort = function (itemID) {
 	// Cache primary values while sorting, since base-field-mapped getField()
 	// calls are relatively expensive
 	var cache = {};
-	sortFields.forEach(function (x) cache[x] = {})
+	sortFields.forEach(x => cache[x] = {})
 	
 	// Get the display field for a row (which might be a placeholder title)
 	function getField(field, row) {
diff --git a/chrome/content/zotero/xpcom/locateManager.js b/chrome/content/zotero/xpcom/locateManager.js
index 253a3c3e77..87222c3188 100644
--- a/chrome/content/zotero/xpcom/locateManager.js
+++ b/chrome/content/zotero/xpcom/locateManager.js
@@ -75,7 +75,7 @@ Zotero.LocateManager = new function() {
 	/**
 	 * Returns an array of all search engines
 	 */
-	this.getEngines = function() _locateEngines.slice(0);
+	this.getEngines = function() { return _locateEngines.slice(0); }
 	
 	/**
 	 * Returns an array of all search engines visible that should be visible in the dropdown
diff --git a/chrome/content/zotero/xpcom/storage.js b/chrome/content/zotero/xpcom/storage.js
index c838cf56f2..aa0d01e618 100644
--- a/chrome/content/zotero/xpcom/storage.js
+++ b/chrome/content/zotero/xpcom/storage.js
@@ -27,8 +27,8 @@
 Zotero.Sync.Storage = new function () {
 	
 	// TEMP
-	this.__defineGetter__("defaultError", function () Zotero.getString('sync.storage.error.default', Zotero.appName));
-	this.__defineGetter__("defaultErrorRestart", function () Zotero.getString('sync.storage.error.defaultRestart', Zotero.appName));
+	this.__defineGetter__("defaultError", function () { return Zotero.getString('sync.storage.error.default', Zotero.appName); });
+	this.__defineGetter__("defaultErrorRestart", function () { return Zotero.getString('sync.storage.error.defaultRestart', Zotero.appName); });
 	
 	var _itemDownloadPercentages = {};
 	
diff --git a/chrome/content/zotero/xpcom/zotero.js b/chrome/content/zotero/xpcom/zotero.js
index f1a5cfe7a7..6ff63dfd00 100644
--- a/chrome/content/zotero/xpcom/zotero.js
+++ b/chrome/content/zotero/xpcom/zotero.js
@@ -72,7 +72,7 @@ Components.utils.import("resource://gre/modules/PluralForm.jsm");
 	 * @property	{Boolean}	locked		Whether all Zotero panes are locked
 	 *										with an overlay
 	 */
-	this.__defineGetter__('locked', function () _locked);
+	this.__defineGetter__('locked', function () { return _locked; });
 	this.__defineSetter__('locked', function (lock) {
 		var wasLocked = _locked;
 		_locked = lock;
@@ -788,7 +788,7 @@ Components.utils.import("resource://gre/modules/PluralForm.jsm");
 				var e = {
 					name: 'NS_ERROR_FILE_ACCESS_DENIED',
 					message: msg,
-					toString: function () this.message
+					toString: function () { return this.message; }
 				};
 				throw (e);
 			}
diff --git a/chrome/content/zotero/zoteroPane.js b/chrome/content/zotero/zoteroPane.js
index d57a1d8d20..1ada0bf5cc 100644
--- a/chrome/content/zotero/zoteroPane.js
+++ b/chrome/content/zotero/zoteroPane.js
@@ -33,7 +33,7 @@ var ZoteroPane = new function()
 	this.itemsView = false;
 	this.progressWindow = false;
 	this._listeners = {};
-	this.__defineGetter__('loaded', function () _loaded);
+	this.__defineGetter__('loaded', function () { return _loaded; });
 	var _lastSelectedItems = [];
 	
 	//Privileged methods
diff --git a/components/zotero-service.js b/components/zotero-service.js
index a11b4aeb97..2be849a88a 100644
--- a/components/zotero-service.js
+++ b/components/zotero-service.js
@@ -327,7 +327,7 @@ function makeZoteroContext(isConnector) {
 	// add connector-related properties
 	zContext.Zotero.isConnector = isConnector;
 	zContext.Zotero.instanceID = instanceID;
-	zContext.Zotero.__defineGetter__("isFirstLoadThisSession", function() isFirstLoadThisSession);
+	zContext.Zotero.__defineGetter__("isFirstLoadThisSession", function() { return isFirstLoadThisSession; });
 };
 
 /**