nl_tokens: Create an instance of this class .
pl_tokens: function HtmlTrackElementList ( ) { var trackElements = arguments . length > 0 && arguments [ 0 ] !== undefined ? arguments [ 0 ] : [ ] ; classCallCheck ( this , HtmlTrackElementList ) ; var list = this ; // eslint-disable-line if ( IS_IE8 ) { list = document . createElement ( 'custom' ) ; for ( var prop in HtmlTrackElementList . prototype ) { if ( <mask> !== 'constructor' ) { list [ prop ] = HtmlTrackElementList . prototype [ prop ] ; } } } list . trackElements_ = [ ] ; /**
       * @memberof HtmlTrackElementList
       * @member {number} length
       *         The current number of `Track`s in the this Trackist.
       * @instance
       */ Object . defineProperty ( list , 'length' , { get : function get$$1 ( ) { return this . trackElements_ . length ; } } ) ; for ( var i = 0 , length = trackElements . length ; i < length ; i ++ ) { list . addTrackElement_ ( trackElements [ i ] ) ; } if ( IS_IE8 ) { return list ; } }