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      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 //
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      8 //     * Redistributions in binary form must reproduce the above
      9 //       copyright notice, this list of conditions and the following
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     11 //       with the distribution.
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     14 //       from this software without specific prior written permission.
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     17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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     26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     27 
     28 // Flags: --allow-natives-syntax --ignition-generators
     29 
     30 // Test instantations of generators.
     31 
     32 // Generators shouldn't allocate stack slots.  This test will abort in debug
     33 // mode if generators have stack slots.
     34 function TestContextAllocation() {
     35   function* g1(a, b, c) { yield 1; return [a, b, c]; }
     36   function* g2() { yield 1; return arguments; }
     37   function* g3() { yield 1; return this; }
     38   function* g4() { var x = 10; yield 1; return x; }
     39   // Temporary variable context allocation
     40   function* g5(l) { "use strict"; yield 1; for (let x in l) { yield x; } }
     41 
     42   g1();
     43   g2();
     44   g3();
     45   g4();
     46   g5(["foo"]);
     47 }
     48 TestContextAllocation();
     49 
     50 
     51 // Test the properties and prototype of a generator object.
     52 function TestGeneratorObject() {
     53   function* g() { yield 1; }
     54 
     55   var iter = g();
     56   assertSame(g.prototype, Object.getPrototypeOf(iter));
     57   assertTrue(iter instanceof g);
     58   assertEquals("Generator", %_ClassOf(iter));
     59   assertEquals("[object Generator]", String(iter));
     60   assertEquals([], Object.getOwnPropertyNames(iter));
     61   assertTrue(iter !== g());
     62   assertEquals("[object Generator]", Object.prototype.toString.call(iter));
     63   var gf = iter.__proto__.constructor;
     64   assertEquals("[object GeneratorFunction]", Object.prototype.toString.call(gf));
     65 
     66   // generators are not constructable.
     67   assertThrows(()=>new g());
     68 }
     69 TestGeneratorObject();
     70 
     71 
     72 // Test the methods of generator objects.
     73 function TestGeneratorObjectMethods() {
     74   function* g() { yield 1; }
     75   var iter = g();
     76 
     77   function TestNonGenerator(non_generator) {
     78     assertThrows(function() { iter.next.call(non_generator); }, TypeError);
     79     assertThrows(function() { iter.next.call(non_generator, 1); }, TypeError);
     80     assertThrows(function() { iter.throw.call(non_generator, 1); }, TypeError);
     81   }
     82 
     83   TestNonGenerator(1);
     84   TestNonGenerator({});
     85   TestNonGenerator(function(){});
     86   TestNonGenerator(g);
     87   TestNonGenerator(g.prototype);
     88 }
     89 TestGeneratorObjectMethods();
     90 
     91 
     92 function TestPrototype() {
     93   function* g() { }
     94 
     95   let g_prototype = g.prototype;
     96   assertEquals([], Reflect.ownKeys(g_prototype));
     97 
     98   let generator_prototype = Object.getPrototypeOf(g_prototype);
     99   assertSame(generator_prototype, Object.getPrototypeOf(g).prototype);
    100 
    101   // Unchanged .prototype
    102   assertSame(g_prototype, Object.getPrototypeOf(g()));
    103 
    104   // Custom object as .prototype
    105   {
    106     let proto = {};
    107     g.prototype = proto;
    108     assertSame(proto, Object.getPrototypeOf(g()));
    109   }
    110 
    111   // Custom non-object as .prototype
    112   g.prototype = null;
    113   assertSame(generator_prototype, Object.getPrototypeOf(g()));
    114 }
    115 TestPrototype();
    116 
    117 
    118 function TestComputedPropertyNames() {
    119   function* f1() { return {[yield]: 42} }
    120   var g1 = f1();
    121   g1.next();
    122   assertEquals(42, g1.next('a').value.a);
    123 
    124   function* f2() { return {['a']: yield} }
    125   var g2 = f2();
    126   g2.next();
    127   assertEquals(42, g2.next(42).value.a);
    128 }
    129 TestComputedPropertyNames();
    130