interceptor.js

var decodedResponse = decodeURIComponent(this.response);
//  The 'adaptive-fmts' parameter stores the video information needed.
var encodedAdaptiveFormats = (decodedResponse.split('adaptive_fmts=')[1] || '').replace(/\+/g, ' ');
var encodedAdaptiveFormatList = encodedAdaptiveFormats.split(',');

//  Convert the encoded URL of adaptive formats into an array of objects since that's a lot easier to work with.
var decodedAdaptiveFormatList = encodedAdaptiveFormatList.map(function(encodedAdaptiveFormat) {
  var decodedAdaptiveFormat = {};

  encodedAdaptiveFormat.split('&').forEach(function(parameterPair) {
    var parameterKeyValue = parameterPair.split('=');
    var key = decodeURIComponent(parameterKeyValue[0]);
    var value = decodeURIComponent(parameterKeyValue[1]);
    decodedAdaptiveFormat[key] = value;
  });

  return decodedAdaptiveFormat;
});

//  Some of the video information received is for 'related videos' which needs to be discarded.
//  To do so, detect type/size on the video information because that indicates its for the current video.
//  Also check that the type is 'video' because it could contain audio information.
videoInfoList = decodedAdaptiveFormatList.filter(function(object) {
  return !!object.type && !!object.size && object.type.indexOf('video') !== -1;
});