nl_tokens: true - > String#at false - > String#codePointAt
pl_tokens: function ( TO_STRING ) { return function ( that , pos ) { var s = String ( _defined ( that ) ) ; var i = _toInteger ( pos ) ; var l = s . length ; var a , b ; if ( i < 0 || i >= l ) return TO_STRING ? '' : undefined ; a = s . charCodeAt ( i ) ; return a < 0xd800 || a > 0xdbff || i + 1 === l || ( b = s . charCodeAt ( i + 1 ) ) < 0xdc00 || b > 0xdfff ? TO_STRING ? s . charAt ( i ) : a : TO_STRING ? s . <mask> ( i , i + 2 ) : ( a - 0xd800 << 10 ) + ( b - 0xdc00 ) + 0x10000 ; } ; }