ES6 computed property names

test/mjsunit/harmony/computed-property-names.js

+// 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: --harmony-computed-property-names
+
+
+(function TestBasicsString() {

[Dmitry Lomov (no reviews), 2014/12/15 10:43:47]

Could you also add (more) tests where computed name values are not immediate
compile-time constant? We should really implement an easy optimization that
reduces `[<literal>] : ..` to `<literal> : ..`.

[arv (Not doing code reviews), 2014/12/15 14:59:01]

I'm not sure it is worth optimizing [literal] since that does seems unlikely to
be used.

I will update the test to make sure these are at least not a PrimaryExpression.

+  var object = {
+    a: 'A',
+    ['b']: 'B',
+    c: 'C',
+    ['d']: 'D',
+  };
+  assertEquals('A', object.a);
+  assertEquals('B', object.b);
+  assertEquals('C', object.c);
+  assertEquals('D', object.d);
+  assertArrayEquals(['a', 'b', 'c', 'd'], Object.keys(object));
+})();
+
+
+(function TestBasicsNumber() {
+  var object = {
+    a: 'A',
+    [1]: 'B',
+    c: 'C',
+    [2]: 'D',
+  };
+  assertEquals('A', object.a);
+  assertEquals('B', object[1]);
+  assertEquals('C', object.c);
+  assertEquals('D', object[2]);
+  // Array indexes first.
+  assertArrayEquals(['1', '2', 'a', 'c'], Object.keys(object));
+})();
+
+
+(function TestBasicsSymbol() {
+  var sym1 = Symbol();
+  var sym2 = Symbol();
+  var object = {
+    a: 'A',
+    [sym1]: 'B',
+    c: 'C',
+    [sym2]: 'D',
+  };
+  assertEquals('A', object.a);
+  assertEquals('B', object[sym1]);
+  assertEquals('C', object.c);
+  assertEquals('D', object[sym2]);
+  assertArrayEquals(['a', 'c'], Object.keys(object));
+  assertArrayEquals([sym1, sym2], Object.getOwnPropertySymbols(object));
+})();
+
+
+(function TestToNameSideEffects() {
+  var counter = 0;
+  var key1 = {
+    toString: function() {
+      assertEquals(0, counter++);
+      return 'b';
+    }
+  };
+  var key2 = {
+    toString: function() {
+      assertEquals(1, counter++);
+      return 'd';
+    }
+  };
+  var object = {
+    a: 'A',
+    [key1]: 'B',
+    c: 'C',
+    [key2]: 'D',
+  };
+  assertEquals(2, counter);
+  assertEquals('A', object.a);
+  assertEquals('B', object.b);
+  assertEquals('C', object.c);
+  assertEquals('D', object.d);
+  assertArrayEquals(['a', 'b', 'c', 'd'], Object.keys(object));
+})();
+
+
+(function TestToNameSideEffectsNumbers() {
+  var counter = 0;
+  var key1 = {
+    valueOf: function() {
+      assertEquals(0, counter++);
+      return 1;
+    },
+    toString: null
+  };
+  var key2 = {
+    valueOf: function() {
+      assertEquals(1, counter++);
+      return 2;
+    },
+    toString: null
+  };
+
+  var object = {
+    a: 'A',
+    [key1]: 'B',
+    c: 'C',
+    [key2]: 'D',
+  };
+  assertEquals(2, counter);
+  assertEquals('A', object.a);
+  assertEquals('B', object[1]);
+  assertEquals('C', object.c);
+  assertEquals('D', object[2]);
+  // Array indexes first.
+  assertArrayEquals(['1', '2', 'a', 'c'], Object.keys(object));
+})();
+
+
+(function TestDoubleName() {
+  var object = {
+    [1.2]: 'A',
+    [1e55]: 'B',
+    [0.000001]: 'C',
+    [-0]: 'D',
+    [Infinity]: 'E',
+    [-Infinity]: 'F',
+    [NaN]: 'G',
+  };
+  assertEquals('A', object['1.2']);
+  assertEquals('B', object['1e+55']);
+  assertEquals('C', object['0.000001']);
+  assertEquals('D', object[0]);
+  assertEquals('E', object[Infinity]);
+  assertEquals('F', object[-Infinity]);
+  assertEquals('G', object[NaN]);
+})();
+
+
+(function TestGetter() {
+  var object = {
+    get ['a']() {
+      return 'A';
+    }
+  };
+  assertEquals('A', object.a);
+
+  object = {
+    get b() {
+      assertUnreachable();
+    },
+    get ['b']() {
+      return 'B';
+    }
+  };
+  assertEquals('B', object.b);
+
+  object = {
+    get c() {
+      assertUnreachable();
+    },
+    get ['c']() {
+      assertUnreachable();
+    },
+    get ['c']() {
+      return 'C';
+    }
+  };
+  assertEquals('C', object.c);
+
+  object = {
+    get ['d']() {
+      assertUnreachable();
+    },
+    get d() {
+      return 'D';
+    }
+  };
+  assertEquals('D', object.d);
+})();
+
+
+(function TestSetter() {
+  var calls = 0;
+  var object = {
+    set ['a'](_) {
+      calls++;
+    }
+  };
+  object.a = 'A';
+  assertEquals(1, calls);
+
+  object = {

[Dmitry Lomov (no reviews), 2014/12/15 10:43:47]

Nit: here and below, set calls to 0 before executing each test case, and
assertEquals(1, calls). This would make test cases independent of each other.

[arv (Not doing code reviews), 2014/12/15 14:59:01]

Done.

+    set b(_) {
+      assertUnreachable();
+    },
+    set ['b'](_) {
+      calls++;
+    }
+  };
+  object.b = 'B';
+  assertEquals(2, calls);
+
+  object = {
+    set c(_) {
+      assertUnreachable()
+    },
+    set ['c'](_) {
+      assertUnreachable()
+    },
+    set ['c'](_) {
+      calls++
+    }
+  };
+  object.c = 'C';
+  assertEquals(3, calls);
+
+  object = {
+    set ['d'](_) {
+      assertUnreachable()
+    },
+    set d(_) {
+      calls++
+    }
+  };
+  object.d = 'D';
+  assertEquals(4, calls);
+})();
+
+
+(function TestDuplicateKeys() {
+  'use strict';
+  // ES5 does not allow duplicate keys.
+  // ES6 does but we haven't changed our code yet.
+
+  var object = {
+    a: 1,
+    ['a']: 2,
+  };
+  assertEquals(2, object.a);
+})();
+
+
+(function TestProto() {
+  var proto = {};
+  var object = {
+    __proto__: proto
+  };
+  assertEquals(proto, Object.getPrototypeOf(object));
+
+  object = {
+    '__proto__': proto
+  };
+  assertEquals(proto, Object.getPrototypeOf(object));
+
+  var object = {
+    ['__proto__']: proto
+  };
+  assertEquals(Object.prototype, Object.getPrototypeOf(object));
+  assertEquals(proto, object.__proto__);
+  assertTrue(object.hasOwnProperty('__proto__'));
+})();