v8/test/mjsunit/dictionary-properties.js

49 lines
1.2 KiB
JavaScript

// Copyright 2014 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Flags: --allow-natives-syntax
// Test loading existent and nonexistent properties from dictionary
// mode objects.
function SlowObject() {
this.foo = 1;
this.bar = 2;
this.qux = 3;
delete this.qux;
assertFalse(%HasFastProperties(this));
}
function SlowObjectWithBaz() {
var o = new SlowObject();
o.baz = 4;
return o;
}
function Load(o) {
return o.baz;
}
for (var i = 0; i < 10; i++) {
var o1 = new SlowObject();
var o2 = SlowObjectWithBaz();
assertEquals(undefined, Load(o1));
assertEquals(4, Load(o2));
}
// Test objects getting optimized as fast prototypes.
function SlowPrototype() {
this.foo = 1;
}
SlowPrototype.prototype.bar = 2;
SlowPrototype.prototype.baz = 3;
delete SlowPrototype.prototype.baz;
new SlowPrototype;
// Prototypes stay fast even after deleting properties.
assertTrue(%HasFastProperties(SlowPrototype.prototype));
var fast_proto = new SlowPrototype();
assertTrue(%HasFastProperties(SlowPrototype.prototype));
assertTrue(%HasFastProperties(fast_proto.__proto__));