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 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. 44assertEquals(Function.prototype[Symbol.hasInstance].call(Array, []), true); 45assertEquals(Function.prototype[Symbol.hasInstance].call({}, {}), false); 46 47// OrdinaryHasInstance passed a non-object argument returns false. 48assertEquals(Function.prototype[Symbol.hasInstance].call(Array, 0), false); 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})(); 68