diff --git a/.eslintignore b/.eslintignore
index c7699ff44..c3a3d13ad 100644
--- a/.eslintignore
+++ b/.eslintignore
@@ -19,6 +19,7 @@ test/views/*.js
 !js/backup.js
 !js/database.js
 !js/logging.js
+!js/i18n.js
 !js/models/conversations.js
 !js/views/attachment_view.js
 !js/views/conversation_search_view.js
diff --git a/background.html b/background.html
index b3a2517b4..9661d8698 100644
--- a/background.html
+++ b/background.html
@@ -909,7 +909,6 @@
   <script type='text/javascript' src='js/expire.js'></script>
   <script type='text/javascript' src='js/conversation_controller.js'></script>
   <script type='text/javascript' src='js/emoji_util.js'></script>
-  <script type='text/javascript' src='js/i18n.js'></script>
 
   <script type='text/javascript' src='js/views/whisper_view.js'></script>
   <script type='text/javascript' src='js/views/last_seen_indicator_view.js'></script>
diff --git a/js/i18n.js b/js/i18n.js
index d5985d29e..4ec0c183c 100644
--- a/js/i18n.js
+++ b/js/i18n.js
@@ -1,29 +1,34 @@
-/*
- * vim: ts=4:sw=4:expandtab
- */
-;(function() {
-    'use strict';
+/* eslint-env node */
 
-    // preload.js loads this, pulling it from main.js (where it was loaded from disk)
-    var messages = window.config.localeMessages;
-    var locale = window.config.locale;
+exports.setup = (locale, messages) => {
+  if (!locale) {
+    throw new Error('i18n: locale parameter is required');
+  }
+  if (!messages) {
+    throw new Error('i18n: messages parameter is required');
+  }
 
-    window.i18n = function (message, substitutions) {
-      if (!messages[message]) {
-        return;
-      }
-      var s = messages[message].message;
-      if (substitutions instanceof Array) {
-        substitutions.forEach(function(sub) {
-          s = s.replace(/\$.+?\$/, sub);
-        });
-      } else if (substitutions) {
-        s = s.replace(/\$.+?\$/, substitutions);
-      }
-      return s;
-    };
+  function getMessage(key, substitutions) {
+    const entry = messages[key];
+    if (!entry) {
+      console.error(`i18n: Attempted to get translation for nonexistent key '${key}'`);
+      return '';
+    }
 
-    i18n.getLocale = function() {
-      return locale;
-    };
-})();
+    const { message } = entry;
+    if (substitutions instanceof Array) {
+      return substitutions.reduce(
+        (result, substitution) => result.replace(/\$.+?\$/, substitution),
+        message
+      );
+    } else if (substitutions) {
+      return message.replace(/\$.+?\$/, substitutions);
+    }
+
+    return message;
+  }
+
+  getMessage.getLocale = () => locale;
+
+  return getMessage;
+};
diff --git a/js/views/timestamp_view.js b/js/views/timestamp_view.js
index 185224ef6..755538d8b 100644
--- a/js/views/timestamp_view.js
+++ b/js/views/timestamp_view.js
@@ -5,15 +5,6 @@
     'use strict';
     window.Whisper = window.Whisper || {};
 
-    moment.updateLocale(i18n.getLocale(), {
-        relativeTime : {
-            s: i18n('timestamp_s') || 'now',
-            m: i18n('timestamp_m') || '1 minute',
-            h: i18n('timestamp_h') || '1 hour'
-        }
-    });
-    moment.locale(i18n.getLocale());
-
     Whisper.TimestampView = Whisper.View.extend({
         initialize: function(options) {
             extension.windows.onClosed(this.clearTimeout.bind(this));
diff --git a/preload.js b/preload.js
index ec554c22b..5eb791caa 100644
--- a/preload.js
+++ b/preload.js
@@ -110,6 +110,19 @@ window.nodeNotifier = require('node-notifier');
 window.ProxyAgent = require('proxy-agent');
 window.moment = require('moment');
 
+const { setup } = require('./js/i18n');
+
+const { locale, localeMessages } = window.config;
+window.i18n = setup(locale, localeMessages);
+window.moment.updateLocale(locale, {
+  relativeTime: {
+    s: window.i18n('timestamp_s'),
+    m: window.i18n('timestamp_m'),
+    h: window.i18n('timestamp_h'),
+  },
+});
+window.moment.locale(locale);
+
 // ES2015+ modules
 const attachmentsPath = Attachments.getPath(app.getPath('userData'));
 const deleteAttachmentData = Attachments.createDeleter(attachmentsPath);
diff --git a/test/i18n_test.js b/test/i18n_test.js
index aea603f5c..6c094487d 100644
--- a/test/i18n_test.js
+++ b/test/i18n_test.js
@@ -1,7 +1,7 @@
 describe('i18n', function() {
   describe('i18n', function() {
-    it('returns undefined for unknown string', function() {
-      assert.strictEqual(i18n('random'), undefined);
+    it('returns empty string for unknown string', function() {
+      assert.strictEqual(i18n('random'), '');
     });
     it('returns message for given string', function() {
       assert.equal(i18n('reportIssue'), 'Report an issue');
diff --git a/test/index.html b/test/index.html
index 5a8c945f4..3384f5986 100644
--- a/test/index.html
+++ b/test/index.html
@@ -562,8 +562,6 @@
   <script type="text/javascript" src="../js/reliable_trigger.js" data-cover></script>
   <script type="text/javascript" src="test.js"></script>
 
-  <script type='text/javascript' src='../js/i18n.js'></script>
-
   <script type='text/javascript' src='../js/registration.js' data-cover></script>
   <script type="text/javascript" src="../js/expire.js" data-cover></script>
   <script type="text/javascript" src="../js/chromium.js" data-cover></script>