nl_tokens: ES6 section 21 . 1 . 5 . 2 . 1 %StringIteratorPrototype% . next ( )
pl_tokens: function StringIteratorNext ( ) { var iterator = this ; var <mask> = UNDEFINED ; var done = true ; if ( ! IS_RECEIVER ( iterator ) || ! HAS_DEFINED_PRIVATE ( iterator , stringIteratorNextIndexSymbol ) ) { throw MakeTypeError ( kIncompatibleMethodReceiver , 'String Iterator.prototype.next' ) ; } var s = GET_PRIVATE ( iterator , stringIteratorIteratedStringSymbol ) ; if ( ! IS_UNDEFINED ( s ) ) { var position = GET_PRIVATE ( iterator , stringIteratorNextIndexSymbol ) ; var length = TO_UINT32 ( s . length ) ; if ( position >= length ) { SET_PRIVATE ( iterator , stringIteratorIteratedStringSymbol , UNDEFINED ) ; } else { var first = % _StringCharCodeAt ( s , position ) ; value = % _StringCharFromCode ( first ) ; done = false ; position ++ ; if ( first >= 0xD800 && first <= 0xDBFF && position < length ) { var second = % _StringCharCodeAt ( s , position ) ; if ( second >= 0xDC00 && second <= 0xDFFF ) { value += % _StringCharFromCode ( second ) ; position ++ ; } } SET_PRIVATE ( iterator , stringIteratorNextIndexSymbol , position ) ; } } return % _CreateIterResultObject ( value , done ) ; }