// Cull non-existent names returned by the trap. var nullProtoAB = Object.create(null, { a: { enumerable: true, configurable: true }, b: { enumerable: false, configurable: true } }); var protoABWithCD = Object.create(nullProtoAB, { c: { enumerable: true, configurable: true }, d: { enumerable: false, configurable: true } }); var returnedNames; var handler = { ownKeys: () => returnedNames }; for (let p of [new Proxy(protoABWithCD, handler), Proxy.revocable(protoABWithCD, handler).proxy]) { returnedNames = [ 'e' ]; var names = Object.keys(p); assertEq(names.length, 0); returnedNames = [ 'c' ]; names = Object.keys(p); assertEq(names.length, 1); assertEq(names[0], 'c'); }