Utils typescript (#2182)

Add typing information to buffer-helper and is-supported.

src/is-supported.js → src/is-supported.ts

@@ -1,8 +1,8 @@
 import { getMediaSource } from './utils/mediasource-helper';
 
-export function isSupported () {
+export function isSupported (): boolean {
   const mediaSource = getMediaSource();
-  const sourceBuffer = window.SourceBuffer || window.WebKitSourceBuffer;
+  const sourceBuffer = SourceBuffer || (window as any).WebKitSourceBuffer;
   const isTypeSupported = mediaSource &&
     typeof mediaSource.isTypeSupported === 'function' &&
     mediaSource.isTypeSupported('video/mp4; codecs="avc1.42E01E,mp4a.40.2"');

src/utils/buffer-helper.js → src/utils/buffer-helper.ts

@@ -8,14 +8,23 @@
  * Also @see https://developer.mozilla.org/en-US/docs/Web/API/HTMLMediaElement/buffered
 */
 
+type BufferTimeRange = {
+  start: number
+  end: number
+}
+
+type Bufferable = {
+  buffered: TimeRanges
+}
+
 export class BufferHelper {
   /**
    * Return true if `media`'s buffered include `position`
-   * @param {HTMLMediaElement|SourceBuffer} media
+   * @param {Bufferable} media
    * @param {number} position
    * @returns {boolean}
    */
-  static isBuffered (media, position) {
+  static isBuffered (media: Bufferable, position: number): boolean {
     try {
       if (media) {
         let buffered = media.buffered;
@@ -33,10 +42,21 @@ export class BufferHelper {
     return false;
   }
 
-  static bufferInfo (media, pos, maxHoleDuration) {
+  static bufferInfo (
+    media: Bufferable,
+    pos: number,
+    maxHoleDuration: number
+  ): {
+    len: number,
+    start: number,
+    end: number,
+    nextStart?: number,
+  } {
     try {
       if (media) {
-        let vbuffered = media.buffered, buffered = [], i;
+        let vbuffered = media.buffered;
+        let buffered: BufferTimeRange[] = [];
+        let i: number;
         for (i = 0; i < vbuffered.length; i++) {
           buffered.push({ start: vbuffered.start(i), end: vbuffered.end(i) });
         }
@@ -51,10 +71,16 @@ export class BufferHelper {
     return { len: 0, start: pos, end: pos, nextStart: undefined };
   }
 
-  static bufferedInfo (buffered, pos, maxHoleDuration) {
-    let buffered2 = [],
-      // bufferStart and bufferEnd are buffer boundaries around current video position
-      bufferLen, bufferStart, bufferEnd, bufferStartNext, i;
+  static bufferedInfo (
+    buffered: BufferTimeRange[],
+    pos: number,
+    maxHoleDuration: number
+  ): {
+    len: number,
+    start: number,
+    end: number,
+    nextStart?: number,
+  } {
     // sort on buffer.start/smaller end (IE does not always return sorted buffered range)
     buffered.sort(function (a, b) {
       let diff = a.start - b.start;
@@ -64,10 +90,12 @@ export class BufferHelper {
         return b.end - a.end;
       }
     });
+
+    let buffered2: BufferTimeRange[] = [];
     // there might be some small holes between buffer time range
     // consider that holes smaller than maxHoleDuration are irrelevant and build another
     // buffer time range representations that discards those holes
-    for (i = 0; i < buffered.length; i++) {
+    for (let i = 0; i < buffered.length; i++) {
       let buf2len = buffered2.length;
       if (buf2len) {
         let buf2end = buffered2[buf2len - 1].end;
@@ -89,7 +117,16 @@ export class BufferHelper {
         buffered2.push(buffered[i]);
       }
     }
-    for (i = 0, bufferLen = 0, bufferStart = bufferEnd = pos; i < buffered2.length; i++) {
+
+    let bufferLen = 0;
+
+    // bufferStartNext can possibly be undefined based on the conditional logic below
+    let bufferStartNext: number | undefined;
+
+    // bufferStart and bufferEnd are buffer boundaries around current video position
+    let bufferStart: number = pos;
+    let bufferEnd: number = pos;
+    for (let i = 0; i < buffered2.length; i++) {
       let start = buffered2[i].start,
         end = buffered2[i].end;
       // logger.log('buf start/end:' + buffered.start(i) + '/' + buffered.end(i));

src/utils/mediasource-helper.ts

@@ -0,0 +1,7 @@
+/**
+ * MediaSource helper
+ */
+
+export function getMediaSource (): typeof MediaSource {
+  return MediaSource || (window as any).WebKitMediaSource;
+}