Use fetch instead of XMLHttpRequest (#292)

client/src/standalone/videos/embed.ts

@@ -6,31 +6,16 @@ import '../../assets/player/peertube-videojs-plugin'
 import 'videojs-dock/dist/videojs-dock.es.js'
 import { VideoDetails } from '../../../../shared'
 
-function loadVideoInfo (videoId: string, callback: (err: Error, res?: VideoDetails) => void) {
-  const xhttp = new XMLHttpRequest()
-  xhttp.onreadystatechange = function () {
-    if (this.readyState === 4 && this.status === 200) {
-      const json = JSON.parse(this.responseText)
-      return callback(null, json)
-    }
-  }
-
-  xhttp.onerror = err => callback(err.error)
-
-  const url = window.location.origin + '/api/v1/videos/' + videoId
-  xhttp.open('GET', url, true)
-  xhttp.send()
+async function loadVideoInfo (videoId: string) {
+  const response = await fetch(window.location.origin + '/api/v1/videos/' + videoId)
+  return response.json();
 }
 
 const urlParts = window.location.href.split('/')
 const videoId = urlParts[urlParts.length - 1]
 
-loadVideoInfo(videoId, (err, videoInfo) => {
-  if (err) {
-    console.error(err)
-    return
-  }
-
+loadVideoInfo(videoId)
+  .then(videoInfo => {
     const videoElement = document.getElementById('video-container') as HTMLVideoElement
     const previewUrl = window.location.origin + videoInfo.previewPath
     videoElement.poster = previewUrl
@@ -56,4 +41,7 @@ loadVideoInfo(videoId, (err, videoInfo) => {
         title: videoInfo.name
       })
     })
-})
+  })
+  .catch(err => {
+    console.error(err);
+  })