nl_tokens: 7 . 4 Operations on Iterator Objects https : // tc39 . github . io / ecma262 / #sec - operations - on - iterator - objects
pl_tokens: function GetIterator ( obj ) { var <mask> = GetMethod ( obj , iteratorSymbol ) ; if ( ! IsCallable ( method ) ) throw new TypeError ( ) ; // from Call var iterator = method . call ( obj ) ; if ( ! IsObject ( iterator ) ) throw new TypeError ( ) ; return iterator ; }