nl_tokens: Checks whether the trap result is consistent with the state of the wrapped target .
pl_tokens: function ( ) { var trap = this . getTrap ( "isFrozen" ) ; if ( trap === undefined ) { // default forwarding behavior return Reflect . isFrozen ( this . target ) ; } var result = trap . call ( this . handler , this . target ) ; <mask> = ! ! result ; // coerce to Boolean var state = Object_isFrozen ( this . target ) ; if ( result !== state ) { if ( result ) { throw new TypeError ( "cannot report unfrozen object as frozen: " + this . target ) ; } else { throw new TypeError ( "cannot report frozen object as unfrozen: " + this . target ) ; } } return state ; }