trap-is-null-target-is-proxy.js (1171B)
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-hasproperty-p 6 description: > 7 If "has" trap is null or undefined, [[HasProperty]] call is properly 8 forwarded to [[ProxyTarget]] (which is also a Proxy object). 9 info: | 10 [[HasProperty]] ( P ) 11 12 [...] 13 5. Let target be O.[[ProxyTarget]]. 14 6. Let trap be ? GetMethod(handler, "has"). 15 7. If trap is undefined, then 16 a. Return ? target.[[HasProperty]](P). 17 features: [Proxy, Symbol, Reflect, Array.prototype.includes] 18 ---*/ 19 20 var stringTarget = new Proxy(new String("str"), {}); 21 var stringProxy = new Proxy(stringTarget, { 22 get: null, 23 }); 24 25 assert(Reflect.has(stringProxy, "length")); 26 assert(0 in stringProxy); 27 assert(!(4 in stringProxy)); 28 29 30 var sym = Symbol(); 31 var target = new Proxy({}, { 32 has: function(_target, key) { 33 return [sym, "6", "foo"].includes(key); 34 }, 35 }); 36 37 var proxy = new Proxy(target, { 38 get: null, 39 }); 40 41 assert(Reflect.has(proxy, sym)); 42 assert("6" in proxy); 43 assert("foo" in Object.create(proxy)); 44 assert(!("bar" in proxy)); 45 46 reportCompare(0, 0);