nl_tokens: naive Set shim
pl_tokens: function CreateSetPolyfill ( ) { return /** @class */ ( function ( ) { function Set ( ) { this . _map = new _Map ( ) ; } Object . defineProperty ( Set . prototype , "size" , { get : function ( ) { return this . _map . size ; } , enumerable : true , configurable : true } ) ; Set . prototype . has = function ( value ) { return this . _map . has ( value ) ; } ; Set . prototype . add = function ( value ) { return this . _map . set ( value , value ) , this ; } ; Set . prototype . delete = function ( value ) { return this . _map . delete ( value ) ; } ; Set . prototype . clear = function ( ) { this . _map . clear ( ) ; } ; Set . prototype . keys = function ( ) { return this . _map . keys ( ) ; } ; Set . prototype . values = function ( ) { return this . _map . values ( ) ; } ; Set . prototype . entries = function ( ) { return this . _map . entries ( ) ; } ; Set . prototype [ "@@iterator" ] = function ( ) { return this . <mask> ( ) ; } ; Set . prototype [ iteratorSymbol ] = function ( ) { return this . keys ( ) ; } ; return Set ; } ( ) ) ; }