fix export initDownloader & tests

__tests__/mainTest.js

@@ -1,4 +1,4 @@
-import RNBackgroundDownloader, { initDownloader } from '../index'
+import RNBackgroundDownloader from '../index'
 import DownloadTask from '../lib/downloadTask'
 import { NativeModules, NativeEventEmitter } from 'react-native'
 
@@ -130,12 +130,18 @@ test('stop', () => {
 })
 
 test('initDownloader', () => {
-  return RNBackgroundDownloader.initDownloader()
+  jest.mock('react-native/Libraries/Utilities/Platform', () => {
-    .then(res => {
+    const Platform = jest.requireActual(
+      'react-native/Libraries/Utilities/Platform'
+    )
+    Platform.OS = 'android'
+    return Platform
+  })
+
+  const res = RNBackgroundDownloader.initDownloader()
   expect(RNBackgroundDownloaderNative.initDownloader).toHaveBeenCalled()
   expect(res).toBe(undefined)
 })
-})
 
 test('checkForExistingDownloads', () => {
   return RNBackgroundDownloader.checkForExistingDownloads()

index.d.ts

@@ -79,7 +79,7 @@ export type EnsureDownloadsAreRunning = () => Promise<void>;
 export interface InitDownloaderOptions {
   type?: 'parallel' | 'sequential' | null;
 }
-export type InitDownloader = (options: InitDownloaderOptions) => Promise<void>;
+export type InitDownloader = (options: InitDownloaderOptions) => undefined;
 
 export interface DownloadOption {
   id: string;

index.ts

@@ -134,6 +134,7 @@ export const Priority = {
 }
 
 export default {
+  initDownloader,
   download,
   checkForExistingDownloads,
   ensureDownloadsAreRunning,