Implement `Conversation.fetchFileAttachments`

ts/backbone/Conversation.ts

@@ -5,14 +5,49 @@ import is from '@sindresorhus/is';
 
 import { Collection as BackboneCollection } from '../types/backbone/Collection';
 import { deferredToPromise } from '../../js/modules/deferred_to_promise';
+import { IndexableBoolean } from '../types/IndexedDB';
 import { Message } from '../types/Message';
 
+const DEFAULT_FETCH_COUNT = 50;
+
 export const fetchVisualMediaAttachments = async ({
   conversationId,
   WhisperMessageCollection,
 }: {
   conversationId: string;
   WhisperMessageCollection: BackboneCollection<Message>;
+}): Promise<Array<Message>> =>
+  fetchFromAttachmentsIndex({
+    name: 'hasVisualMediaAttachments',
+    conversationId,
+    WhisperMessageCollection,
+    count: DEFAULT_FETCH_COUNT,
+  });
+
+export const fetchFileAttachments = async ({
+  conversationId,
+  WhisperMessageCollection,
+}: {
+  conversationId: string;
+  WhisperMessageCollection: BackboneCollection<Message>;
+}): Promise<Array<Message>> =>
+  fetchFromAttachmentsIndex({
+    name: 'hasFileAttachments',
+    conversationId,
+    WhisperMessageCollection,
+    count: DEFAULT_FETCH_COUNT,
+  });
+
+const fetchFromAttachmentsIndex = async ({
+  name,
+  conversationId,
+  WhisperMessageCollection,
+  count,
+}: {
+  name: 'hasVisualMediaAttachments' | 'hasFileAttachments';
+  conversationId: string;
+  WhisperMessageCollection: BackboneCollection<Message>;
+  count: number;
 }): Promise<Array<Message>> => {
   if (!is.string(conversationId)) {
     throw new TypeError("'conversationId' is required");
@@ -25,16 +60,16 @@ export const fetchVisualMediaAttachments = async ({
   const collection = new WhisperMessageCollection();
   const lowerReceivedAt = 0;
   const upperReceivedAt = Number.MAX_VALUE;
-  const hasVisualMediaAttachments = 1;
+  const condition: IndexableBoolean = 1;
   await deferredToPromise(
     collection.fetch({
       index: {
-        name: 'hasVisualMediaAttachments',
+        name,
-        lower: [conversationId, lowerReceivedAt, hasVisualMediaAttachments],
+        lower: [conversationId, lowerReceivedAt, condition],
-        upper: [conversationId, upperReceivedAt, hasVisualMediaAttachments],
+        upper: [conversationId, upperReceivedAt, condition],
         order: 'desc',
       },
-      limit: 50,
+      limit: count,
     })
   );