trap-is-null-target-is-proxy.js (1268B)
1 // Copyright (C) 2020 Alexey Shvayka. All rights reserved. 2 // This code is governed by the BSD license found in the LICENSE file. 3 4 /*--- 5 esid: sec-proxy-object-internal-methods-and-internal-slots-set-p-v-receiver 6 description: > 7 If "set" trap is null or undefined, [[Set]] call is properly 8 forwarded to [[ProxyTarget]] (which is also a Proxy object). 9 info: | 10 [[Set]] ( P, V, Receiver ) 11 12 [...] 13 5. Let target be O.[[ProxyTarget]]. 14 6. Let trap be ? GetMethod(handler, "set"). 15 7. If trap is undefined, then 16 a. Return ? target.[[Set]](P, V, Receiver). 17 features: [Proxy, Reflect] 18 includes: [compareArray.js] 19 ---*/ 20 21 var array = [1, 2, 3]; 22 var arrayTarget = new Proxy(array, {}); 23 var arrayProxy = new Proxy(arrayTarget, { 24 set: null, 25 }); 26 27 arrayProxy.length = 0; 28 assert.compareArray(array, []); 29 30 Object.preventExtensions(array); 31 32 assert(!Reflect.set(arrayProxy, "foo", 2)); 33 assert.throws(TypeError, function() { 34 "use strict"; 35 arrayProxy[0] = 3; 36 }); 37 38 39 var string = new String("str"); 40 var stringTarget = new Proxy(string, {}); 41 var stringProxy = new Proxy(stringTarget, { 42 set: null, 43 }); 44 45 stringProxy[4] = 1; 46 assert.sameValue(string[4], 1); 47 48 assert(!Reflect.set(stringProxy, "0", "s")); 49 assert(!Reflect.set(stringProxy, "length", 3)); 50 51 reportCompare(0, 0);