Ben Murdoch | 097c5b2 | 2016-05-18 11:27:45 +0100 | [diff] [blame] | 1 | // Copyright 2016 the V8 project authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style license that can be |
| 3 | // found in the LICENSE file. |
| 4 | |
Ben Murdoch | 097c5b2 | 2016-05-18 11:27:45 +0100 | [diff] [blame] | 5 | // Make sure it's an error if @@hasInstance isn't a function. |
| 6 | (function() { |
| 7 | var F = {}; |
| 8 | F[Symbol.hasInstance] = null; |
| 9 | assertThrows(function() { 0 instanceof F; }, TypeError); |
| 10 | })(); |
| 11 | |
| 12 | // Make sure the result is coerced to boolean. |
| 13 | (function() { |
| 14 | var F = {}; |
| 15 | F[Symbol.hasInstance] = function() { return undefined; }; |
| 16 | assertEquals(0 instanceof F, false); |
| 17 | F[Symbol.hasInstance] = function() { return null; }; |
| 18 | assertEquals(0 instanceof F, false); |
| 19 | F[Symbol.hasInstance] = function() { return true; }; |
| 20 | assertEquals(0 instanceof F, true); |
| 21 | })(); |
| 22 | |
| 23 | // Make sure if @@hasInstance throws, we catch it. |
| 24 | (function() { |
| 25 | var F = {}; |
| 26 | F[Symbol.hasInstance] = function() { throw new Error("always throws"); } |
| 27 | try { |
| 28 | 0 instanceof F; |
| 29 | } catch (e) { |
| 30 | assertEquals(e.message, "always throws"); |
| 31 | } |
| 32 | })(); |
| 33 | |
| 34 | // @@hasInstance works for bound functions. |
| 35 | (function() { |
| 36 | var BC = function() {}; |
| 37 | var bc = new BC(); |
| 38 | var bound = BC.bind(); |
| 39 | assertEquals(bound[Symbol.hasInstance](bc), true); |
| 40 | assertEquals(bound[Symbol.hasInstance]([]), false); |
| 41 | })(); |
| 42 | |
| 43 | // if OrdinaryHasInstance is passed a non-callable receiver, return false. |
| 44 | assertEquals(Function.prototype[Symbol.hasInstance].call(Array, []), true); |
| 45 | assertEquals(Function.prototype[Symbol.hasInstance].call({}, {}), false); |
| 46 | |
| 47 | // OrdinaryHasInstance passed a non-object argument returns false. |
| 48 | assertEquals(Function.prototype[Symbol.hasInstance].call(Array, 0), false); |
Ben Murdoch | c561043 | 2016-08-08 18:44:38 +0100 | [diff] [blame] | 49 | |
| 50 | // Cannot assign to @@hasInstance with %FunctionPrototype%. |
| 51 | (function() { |
| 52 | "use strict"; |
| 53 | function F() {} |
| 54 | assertThrows(function() { F[Symbol.hasInstance] = (v) => v }, TypeError); |
| 55 | })(); |
| 56 | |
| 57 | // Check correct invocation of @@hasInstance handler on function instance. |
| 58 | (function() { |
| 59 | function F() {} |
| 60 | var counter = 0; |
| 61 | var proto = Object.getPrototypeOf(F); |
| 62 | Object.setPrototypeOf(F, null); |
| 63 | F[Symbol.hasInstance] = function(v) { ++counter; return true }; |
| 64 | Object.setPrototypeOf(F, proto); |
| 65 | assertTrue(1 instanceof F); |
| 66 | assertEquals(1, counter); |
| 67 | })(); |