improve typescript

index.ts

@@ -0,0 +1,140 @@
+import { NativeModules, NativeEventEmitter } from 'react-native'
+import DownloadTask from './lib/DownloadTask'
+
+const { RNBackgroundDownloader } = NativeModules
+const RNBackgroundDownloaderEmitter = new NativeEventEmitter(RNBackgroundDownloader)
+
+const tasksMap = new Map()
+let headers = {}
+
+RNBackgroundDownloaderEmitter.addListener('downloadProgress', events => {
+  for (const event of events) {
+    const task = tasksMap.get(event.id)
+    task?.onProgress(event.percent, event.written, event.total)
+  }
+})
+
+RNBackgroundDownloaderEmitter.addListener('downloadComplete', ({ id, location }) => {
+  const task = tasksMap.get(id)
+  task?.onDone({ location })
+
+  tasksMap.delete(id)
+})
+
+RNBackgroundDownloaderEmitter.addListener('downloadFailed', event => {
+  const task = tasksMap.get(event.id)
+  task?.onError(event.error, event.errorcode)
+
+  tasksMap.delete(event.id)
+})
+
+RNBackgroundDownloaderEmitter.addListener('downloadBegin', ({ id, expectedBytes, headers }) => {
+  const task = tasksMap.get(id)
+  task?.onBegin({ expectedBytes, headers })
+})
+
+export function setHeaders (h = {}) {
+  if (typeof h !== 'object')
+    throw new Error('[RNBackgroundDownloader] headers must be an object')
+
+  headers = h
+}
+
+export function checkForExistingDownloads () {
+  return RNBackgroundDownloader.checkForExistingDownloads()
+    .then(foundTasks => {
+      return foundTasks.map(taskInfo => {
+        // SECOND ARGUMENT RE-ASSIGNS EVENT HANDLERS
+        const task = new DownloadTask(taskInfo, tasksMap.get(taskInfo.id))
+
+        if (taskInfo.state === RNBackgroundDownloader.TaskRunning) {
+          task.state = 'DOWNLOADING'
+        } else if (taskInfo.state === RNBackgroundDownloader.TaskSuspended) {
+          task.state = 'PAUSED'
+        } else if (taskInfo.state === RNBackgroundDownloader.TaskCanceling) {
+          task.stop()
+          return null
+        } else if (taskInfo.state === RNBackgroundDownloader.TaskCompleted) {
+          if (taskInfo.bytesWritten === taskInfo.totalBytes)
+            task.state = 'DONE'
+          else
+            // IOS completed the download but it was not done.
+            return null
+        }
+        tasksMap.set(taskInfo.id, task)
+        return task
+      }).filter(task => task !== null)
+    })
+}
+
+export function ensureDownloadsAreRunning () {
+  return checkForExistingDownloads()
+    .then(tasks => {
+      for (const task of tasks)
+        if (task.state === 'DOWNLOADING') {
+          task.pause()
+          task.resume()
+        }
+    })
+}
+
+export function completeHandler (jobId) {
+  return RNBackgroundDownloader.completeHandler(jobId)
+}
+
+type DownloadOptions = {
+  id: string,
+  url: string,
+  destination: string,
+  headers?: object,
+  metadata?: object,
+}
+
+export function download (options : DownloadOptions) {
+  if (!options.id || !options.url || !options.destination)
+    throw new Error('[RNBackgroundDownloader] id, url and destination are required')
+
+  options.headers = { ...headers, ...(options.headers || {}) }
+
+  if (!(options.metadata && typeof options.metadata === 'object'))
+    options.metadata = {}
+
+  const task = new DownloadTask({
+    id: options.id,
+    metadata: options.metadata,
+  })
+  tasksMap.set(options.id, task)
+
+  RNBackgroundDownloader.download({
+    ...options,
+    metadata: JSON.stringify(options.metadata),
+  })
+
+  return task
+}
+
+export const directories = {
+  documents: RNBackgroundDownloader.documents,
+}
+
+export const Network = {
+  WIFI_ONLY: RNBackgroundDownloader.OnlyWifi,
+  ALL: RNBackgroundDownloader.AllNetworks,
+}
+
+export const Priority = {
+  HIGH: RNBackgroundDownloader.PriorityHigh,
+  MEDIUM: RNBackgroundDownloader.PriorityNormal,
+  LOW: RNBackgroundDownloader.PriorityLow,
+}
+
+export default {
+  download,
+  checkForExistingDownloads,
+  ensureDownloadsAreRunning,
+  completeHandler,
+  setHeaders,
+  directories,
+  Network,
+  Priority,
+}