diff --git a/js/modules/types/attachment.js b/js/modules/types/attachment.js
index 25e58bb95..cb67b7f1d 100644
--- a/js/modules/types/attachment.js
+++ b/js/modules/types/attachment.js
@@ -1,6 +1,6 @@
 const is = require('@sindresorhus/is');
 
-const MIME = require('./mime');
+const MIME = require('../../../ts/types/MIME');
 const { arrayBufferToBlob, blobToArrayBuffer, dataURLToBlob } = require('blob-util');
 const { autoOrientImage } = require('../auto_orient_image');
 const { migrateDataToFileSystem } = require('./attachment/migrate_data_to_file_system');
diff --git a/js/modules/types/mime.js b/js/modules/types/mime.js
deleted file mode 100644
index b149aead4..000000000
--- a/js/modules/types/mime.js
+++ /dev/null
@@ -1,10 +0,0 @@
-exports.isJPEG = mimeType =>
-  mimeType === 'image/jpeg';
-
-exports.isVideo = mimeType =>
-  mimeType.startsWith('video/') && mimeType !== 'video/wmv';
-
-exports.isImage = mimeType =>
-  mimeType.startsWith('image/') && mimeType !== 'image/tiff';
-
-exports.isAudio = mimeType => mimeType.startsWith('audio/');
diff --git a/preload.js b/preload.js
index 24eada452..d35da5a88 100644
--- a/preload.js
+++ b/preload.js
@@ -191,7 +191,7 @@ window.Signal.Types.Conversation = require('./ts/types/Conversation');
 window.Signal.Types.Errors = require('./js/modules/types/errors');
 
 window.Signal.Types.Message = Message;
-window.Signal.Types.MIME = require('./js/modules/types/mime');
+window.Signal.Types.MIME = require('./ts/types/MIME');
 window.Signal.Types.Settings = require('./js/modules/types/settings');
 
 window.Signal.Views = {};
diff --git a/test/modules/types/mime_test.js b/test/modules/types/mime_test.js
index b56f831c4..ab62bc343 100644
--- a/test/modules/types/mime_test.js
+++ b/test/modules/types/mime_test.js
@@ -1,6 +1,6 @@
 const { assert } = require('chai');
 
-const MIME = require('../../../js/modules/types/mime');
+const MIME = require('../../../ts/types/MIME');
 
 
 describe('MIME', () => {
diff --git a/ts/components/conversation/Quote.tsx b/ts/components/conversation/Quote.tsx
index 3e541f7ce..417448dd4 100644
--- a/ts/components/conversation/Quote.tsx
+++ b/ts/components/conversation/Quote.tsx
@@ -1,8 +1,7 @@
 import React from 'react';
 import classnames from 'classnames';
 
-// @ts-ignore
-import Mime from '../../../js/modules/types/mime';
+import * as MIME from '../../../ts/types/MIME';
 
 
 interface Props {
@@ -92,17 +91,17 @@ export class Quote extends React.Component<Props, {}> {
     const { contentType, thumbnail } = first;
     const objectUrl = getObjectUrl(thumbnail);
 
-    if (Mime.isVideo(contentType)) {
+    if (MIME.isVideo(contentType)) {
       return objectUrl
         ? this.renderImage(objectUrl, 'play')
         : this.renderIcon('movie');
     }
-    if (Mime.isImage(contentType)) {
+    if (MIME.isImage(contentType)) {
       return objectUrl
         ? this.renderImage(objectUrl)
         : this.renderIcon('image');
     }
-    if (Mime.isAudio(contentType)) {
+    if (MIME.isAudio(contentType)) {
       return this.renderIcon('microphone');
     }
 
@@ -123,16 +122,16 @@ export class Quote extends React.Component<Props, {}> {
     const first = attachments[0];
     const { contentType, fileName, isVoiceMessage } = first;
 
-    if (Mime.isVideo(contentType)) {
+    if (MIME.isVideo(contentType)) {
       return <div className="type-label">{i18n('video')}</div>;
     }
-    if (Mime.isImage(contentType)) {
+    if (MIME.isImage(contentType)) {
       return <div className="type-label">{i18n('photo')}</div>;
     }
-    if (Mime.isAudio(contentType) && isVoiceMessage) {
+    if (MIME.isAudio(contentType) && isVoiceMessage) {
       return <div className="type-label">{i18n('voiceMessage')}</div>;
     }
-    if (Mime.isAudio(contentType)) {
+    if (MIME.isAudio(contentType)) {
       return <div className="type-label">{i18n('audio')}</div>;
     }
 
diff --git a/ts/styleguide/StyleGuideUtil.ts b/ts/styleguide/StyleGuideUtil.ts
index 35149e196..0d61d39fe 100644
--- a/ts/styleguide/StyleGuideUtil.ts
+++ b/ts/styleguide/StyleGuideUtil.ts
@@ -20,8 +20,7 @@ export { BackboneWrapper } from '../components/utility/BackboneWrapper';
 import { Quote } from '../components/conversation/Quote';
 import * as HTML from '../html';
 
-// @ts-ignore
-import MIME from '../../js/modules/types/mime';
+import * as MIME from '../../ts/types/MIME';
 
 // TypeScript wants two things when you import:
 //   1) a normal typescript file
diff --git a/ts/types/MIME.ts b/ts/types/MIME.ts
index ade12d7d5..ed1e3b5fd 100644
--- a/ts/types/MIME.ts
+++ b/ts/types/MIME.ts
@@ -1 +1,14 @@
 export type MIMEType = string & { _mimeTypeBrand: any };
+
+
+export const isVideo = (value: MIMEType): boolean =>
+  value.startsWith('video/') && value !== 'video/wmv';
+
+export const isImage = (value: MIMEType): boolean =>
+  value.startsWith('image/') && value !== 'image/tiff';
+
+export const isAudio = (value: MIMEType): boolean =>
+  value.startsWith('audio/');
+
+export const isJPEG = (value: MIMEType): boolean =>
+  value === 'image/jpeg';