nl_tokens: If name denotes a sealed property check whether handler rejects .
pl_tokens: function ( name ) { "use strict" ; var trap = this . getTrap ( "deleteProperty" ) ; if ( trap === undefined ) { // default forwarding behavior return Reflect . deleteProperty ( this . target , name ) ; } name = String ( name ) ; var res = trap . call ( this . handler , this . target , name ) ; res = ! ! res ; // coerce to Boolean if ( res === true ) { if ( isSealed ( name , this . target ) ) { throw new TypeError ( "property '" + <mask> + "' is non-configurable " + "and can't be deleted" ) ; } } return res ; }