diff --git a/chrome/content/zotero/xpcom/date.js b/chrome/content/zotero/xpcom/date.js
index db31cd1d1d..33381eedda 100644
--- a/chrome/content/zotero/xpcom/date.js
+++ b/chrome/content/zotero/xpcom/date.js
@@ -47,46 +47,41 @@ Zotero.Date = new function(){
 			throw new Error("Unimplemented");
 		}
 		
-		return Zotero.HTTP.request(
-			'GET', 'resource://zotero/schema/dateFormats.json', { responseType: 'json' }
-		).then(function(xmlhttp) {
-			var json = xmlhttp.response;
-			
-			var locale = Zotero.locale;
-			var english = locale.startsWith('en');
-			// If no exact match, try first two characters ('de')
-			if (!json[locale]) {
-				locale = locale.substr(0, 2);
+		var json = JSON.parse(Zotero.File.getResource('schema/dateFormats.json'));
+		var locale = Zotero.locale;
+		var english = locale.startsWith('en');
+		// If no exact match, try first two characters ('de')
+		if (!json[locale]) {
+			locale = locale.substr(0, 2);
+		}
+		// Try first two characters repeated ('de-DE')
+		if (!json[locale]) {
+			locale = locale + "-" + locale.toUpperCase();
+		}
+		// Look for another locale with same first two characters
+		if (!json[locale]) {
+			let sameLang = Object.keys(json).filter(l => l.startsWith(locale.substr(0, 2)));
+			if (sameLang.length) {
+				locale = sameLang[0];
 			}
-			// Try first two characters repeated ('de-DE')
-			if (!json[locale]) {
-				locale = locale + "-" + locale.toUpperCase();
-			}
-			// Look for another locale with same first two characters
-			if (!json[locale]) {
-				let sameLang = Object.keys(json).filter(l => l.startsWith(locale.substr(0, 2)));
-				if (sameLang.length) {
-					locale = sameLang[0];
-				}
-			}
-			// If all else fails, use English
-			if (!json[locale]) {
-				locale = 'en-US';
-				english = true;
-			}
-			_months = json[locale];
+		}
+		// If all else fails, use English
+		if (!json[locale]) {
+			locale = 'en-US';
+			english = true;
+		}
+		_months = json[locale];
 
-			// Add English versions if not already added
-			if (english) {
-				_monthsWithEnglish = _months;
+		// Add English versions if not already added
+		if (english) {
+			_monthsWithEnglish = _months;
+		}
+		else {
+			_monthsWithEnglish = {};
+			for (let key in _months) {
+				_monthsWithEnglish[key] = _months[key].concat(json['en-US'][key]);
 			}
-			else {
-				_monthsWithEnglish = {};
-				for (let key in _months) {
-					_monthsWithEnglish[key] = _months[key].concat(json['en-US'][key]);
-				}
-			}
-		});
+		}
 	};
 	
 	
diff --git a/chrome/content/zotero/xpcom/file.js b/chrome/content/zotero/xpcom/file.js
index 59dc2e9850..83940dcf10 100644
--- a/chrome/content/zotero/xpcom/file.js
+++ b/chrome/content/zotero/xpcom/file.js
@@ -339,6 +339,13 @@ Zotero.File = new function(){
 		xmlhttp.send(null);
 		return xmlhttp.responseText;
 	}
+
+	/*
+	 * Returns the contents of the given local resource.
+	 */
+	this.getResource = function (res) {
+		return getContentsFromURL(`resource://zotero/${res}`);
+	}
 	
 	
 	/*
diff --git a/chrome/content/zotero/xpcom/zotero.js b/chrome/content/zotero/xpcom/zotero.js
index 509aa73b89..3c57f75e65 100644
--- a/chrome/content/zotero/xpcom/zotero.js
+++ b/chrome/content/zotero/xpcom/zotero.js
@@ -824,7 +824,7 @@ Services.scriptloader.loadSubScript("resource://zotero/polyfill.js");
 			// Initialize keyboard shortcuts
 			Zotero.Keys.init();
 			
-			yield Zotero.Date.init();
+			Zotero.Date.init();
 			Zotero.LocateManager.init();
 			yield Zotero.ID.init();
 			yield Zotero.Collections.init();
diff --git a/test/tests/dateTest.js b/test/tests/dateTest.js
index 9c416bc4c1..4330f94f10 100644
--- a/test/tests/dateTest.js
+++ b/test/tests/dateTest.js
@@ -28,7 +28,7 @@ describe("Zotero.Date", function() {
 			beforeEach(function* () {
 				if (Zotero.locale != 'en-US') {
 					Zotero.locale = 'en-US';
-					yield Zotero.Date.init();
+					Zotero.Date.init();
 				}
 			});
 			
@@ -52,7 +52,7 @@ describe("Zotero.Date", function() {
 			
 			it("should resolve to English from unknown locale", function* () {
 				Zotero.locale = 'zz';
-				yield Zotero.Date.init();
+				Zotero.Date.init();
 				let months = Zotero.Date.getMonths().short;
 				assert.lengthOf(months, 12);
 				assert.sameMembers(months, englishShort);
@@ -60,7 +60,7 @@ describe("Zotero.Date", function() {
 			
 			it("shouldn't repeat English with unknown locale", function* () {
 				Zotero.locale = 'zz';
-				yield Zotero.Date.init();
+				Zotero.Date.init();
 				let months = Zotero.Date.getMonths(true).short;
 				assert.lengthOf(months, 12);
 				assert.sameMembers(months, englishShort);
@@ -71,7 +71,7 @@ describe("Zotero.Date", function() {
 			beforeEach(function* () {
 				if (Zotero.locale != 'fr-FR') {
 					Zotero.locale = 'fr-FR';
-					yield Zotero.Date.init();
+					Zotero.Date.init();
 				}
 			});
 			
@@ -101,7 +101,7 @@ describe("Zotero.Date", function() {
 			
 			it("should resolve from two-letter locale", function* () {
 				Zotero.locale = 'fr';
-				yield Zotero.Date.init();
+				Zotero.Date.init();
 				let months = Zotero.Date.getMonths().short;
 				assert.lengthOf(months, 12);
 				assert.sameMembers(months, frenchShort);
@@ -109,7 +109,7 @@ describe("Zotero.Date", function() {
 			
 			it("should resolve from unknown four-letter locale with common prefix", function* () {
 				Zotero.locale = 'fr-ZZ';
-				yield Zotero.Date.init();
+				Zotero.Date.init();
 				let months = Zotero.Date.getMonths().short;
 				assert.lengthOf(months, 12);
 				assert.sameMembers(months, frenchShort);