1 // Copyright 2013 the V8 project authors. All rights reserved. 2 // Redistribution and use in source and binary forms, with or without 3 // modification, are permitted provided that the following conditions are 4 // met: 5 // 6 // * Redistributions of source code must retain the above copyright 7 // notice, this list of conditions and the following disclaimer. 8 // * Redistributions in binary form must reproduce the above 9 // copyright notice, this list of conditions and the following 10 // disclaimer in the documentation and/or other materials provided 11 // with the distribution. 12 // * Neither the name of Google Inc. nor the names of its 13 // contributors may be used to endorse or promote products derived 14 // from this software without specific prior written permission. 15 // 16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 28 // Test aspects of the generator runtime. 29 30 // See: 31 // http://people.mozilla.org/~jorendorff/es6-draft.html#sec-generatorfunction-objects 32 33 function f() { "use strict"; } 34 function* g() { yield 1; } 35 var GeneratorFunctionPrototype = Object.getPrototypeOf(g); 36 var GeneratorFunction = GeneratorFunctionPrototype.constructor; 37 var GeneratorObjectPrototype = GeneratorFunctionPrototype.prototype; 38 var IteratorPrototype = Object.getPrototypeOf(GeneratorObjectPrototype); 39 40 // A generator function should have the same set of properties as any 41 // other function. 42 function TestGeneratorFunctionInstance() { 43 var f_own_property_names = Object.getOwnPropertyNames(f); 44 var g_own_property_names = Object.getOwnPropertyNames(g); 45 46 f_own_property_names.sort(); 47 g_own_property_names.sort(); 48 49 assertArrayEquals(f_own_property_names, g_own_property_names); 50 var i; 51 for (i = 0; i < f_own_property_names.length; i++) { 52 var prop = f_own_property_names[i]; 53 var f_desc = Object.getOwnPropertyDescriptor(f, prop); 54 var g_desc = Object.getOwnPropertyDescriptor(g, prop); 55 assertEquals(f_desc.configurable, g_desc.configurable, prop); 56 assertEquals(f_desc.writable, g_desc.writable, prop); 57 assertEquals(f_desc.enumerable, g_desc.enumerable, prop); 58 } 59 } 60 TestGeneratorFunctionInstance(); 61 62 63 // Generators have an additional object interposed in the chain between 64 // themselves and Function.prototype. 65 function TestGeneratorFunctionPrototype() { 66 // Sanity check. 67 assertSame(Object.getPrototypeOf(f), Function.prototype); 68 assertFalse(GeneratorFunctionPrototype === Function.prototype); 69 assertSame(Function.prototype, 70 Object.getPrototypeOf(GeneratorFunctionPrototype)); 71 assertSame(GeneratorFunctionPrototype, 72 Object.getPrototypeOf(function* () {})); 73 assertSame("object", typeof GeneratorFunctionPrototype); 74 75 var constructor_desc = Object.getOwnPropertyDescriptor( 76 GeneratorFunctionPrototype, "constructor"); 77 assertTrue(constructor_desc !== undefined); 78 assertSame(GeneratorFunction, constructor_desc.value); 79 assertFalse(constructor_desc.writable); 80 assertFalse(constructor_desc.enumerable); 81 assertTrue(constructor_desc.configurable); 82 83 var prototype_desc = Object.getOwnPropertyDescriptor( 84 GeneratorFunctionPrototype, "prototype"); 85 assertTrue(prototype_desc !== undefined); 86 assertSame(GeneratorObjectPrototype, prototype_desc.value); 87 assertFalse(prototype_desc.writable); 88 assertFalse(prototype_desc.enumerable); 89 assertTrue(prototype_desc.configurable); 90 } 91 TestGeneratorFunctionPrototype(); 92 93 94 // Functions that we associate with generator objects are actually defined by 95 // a common prototype. 96 function TestGeneratorObjectPrototype() { 97 assertSame(IteratorPrototype, 98 Object.getPrototypeOf(GeneratorObjectPrototype)); 99 assertSame(GeneratorObjectPrototype, 100 Object.getPrototypeOf((function*(){yield 1}).prototype)); 101 102 var expected_property_names = ["next", "throw", "constructor"]; 103 var found_property_names = 104 Object.getOwnPropertyNames(GeneratorObjectPrototype); 105 106 expected_property_names.sort(); 107 found_property_names.sort(); 108 109 assertArrayEquals(expected_property_names, found_property_names); 110 111 var constructor_desc = Object.getOwnPropertyDescriptor( 112 GeneratorObjectPrototype, "constructor"); 113 assertTrue(constructor_desc !== undefined); 114 assertFalse(constructor_desc.writable); 115 assertFalse(constructor_desc.enumerable); 116 assertTrue(constructor_desc.configurable); 117 118 var next_desc = Object.getOwnPropertyDescriptor(GeneratorObjectPrototype, 119 "next"); 120 assertTrue(next_desc !== undefined); 121 assertTrue(next_desc.writable); 122 assertFalse(next_desc.enumerable); 123 assertTrue(next_desc.configurable); 124 125 var throw_desc = Object.getOwnPropertyDescriptor(GeneratorObjectPrototype, 126 "throw"); 127 assertTrue(throw_desc !== undefined); 128 assertTrue(throw_desc.writable); 129 assertFalse(throw_desc.enumerable); 130 assertTrue(throw_desc.configurable); 131 } 132 TestGeneratorObjectPrototype(); 133 134 135 // This tests the object that would be called "GeneratorFunction", if it were 136 // like "Function". 137 function TestGeneratorFunction() { 138 assertSame(GeneratorFunctionPrototype, GeneratorFunction.prototype); 139 assertTrue(g instanceof GeneratorFunction); 140 141 assertSame(Function, Object.getPrototypeOf(GeneratorFunction)); 142 assertTrue(g instanceof Function); 143 144 assertEquals("function* g() { yield 1; }", g.toString()); 145 146 // Not all functions are generators. 147 assertTrue(f instanceof Function); // Sanity check. 148 assertTrue(!(f instanceof GeneratorFunction)); 149 150 assertTrue((new GeneratorFunction()) instanceof GeneratorFunction); 151 assertTrue(GeneratorFunction() instanceof GeneratorFunction); 152 153 // ES6 draft 04-14-15, section 25.2.2.2 154 var prototype_desc = Object.getOwnPropertyDescriptor(GeneratorFunction, 155 "prototype"); 156 assertFalse(prototype_desc.writable); 157 assertFalse(prototype_desc.enumerable); 158 assertFalse(prototype_desc.configurable); 159 } 160 TestGeneratorFunction(); 161 162 163 function TestPerGeneratorPrototype() { 164 assertTrue((function*(){}).prototype !== (function*(){}).prototype); 165 assertTrue((function*(){}).prototype !== g.prototype); 166 assertSame(GeneratorObjectPrototype, Object.getPrototypeOf(g.prototype)); 167 assertTrue(!(g.prototype instanceof Function)); 168 assertSame(typeof (g.prototype), "object"); 169 170 assertArrayEquals([], Object.getOwnPropertyNames(g.prototype)); 171 } 172 TestPerGeneratorPrototype(); 173
