ES6: Adding support for size to Set and Map

test/mjsunit/harmony/collections.js

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 // modification, are permitted provided that the following conditions are
 // met:
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 //     * Redistributions of source code must retain the above copyright
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@@ skipping 295 matching lines @@
       }
     }
   }
 }
 TestBogusReceivers(bogusReceiversTestSet);
 
 
 // Stress Test
 // There is a proposed stress-test available at the es-discuss mailing list
 // which cannot be reasonably automated.  Check it out by hand if you like:
-// https://mail.mozilla.org/pipermail/es-discuss/2011-May/014096.html
+// https://mail.mozilla.org/pipermail/es-discuss/2011-May/014096.html
+
+
+// Set and Map Set size

[Michael Starzinger, 2012/11/06 09:32:40]

Comment seems to contain a typo.

[arv (Not doing code reviews), 2012/11/06 16:02:33]

Done.

+var setSizeDescriptor = Object.getOwnPropertyDescriptor(Set.prototype, 'size');
+assertEquals(undefined, setSizeDescriptor.value);
+assertEquals(undefined, setSizeDescriptor.set);
+assertTrue(setSizeDescriptor.get instanceof Function);
+assertFalse(setSizeDescriptor.enumerable);

[Michael Starzinger, 2012/11/06 09:32:40]

I couldn't find the expected value of the attributes (i.e. enumerable and
configurable) in the draft spec. Is that still unspeced?

[arv (Not doing code reviews), 2012/11/06 16:02:33]

Last sentence of last paragraph in the introduction to clause 15:

Every other property described in this clause has the attributes { [[Writable]]:
true, [[Enumerable]]: false, [[Configurable]]: true } unless otherwise
specified.

[Michael Starzinger, 2012/11/06 17:47:55]

Ah, yes, I didn't see this sentence. To be pedantic (as Andreas pointed out),
this sentence is talking about data properties (as it contains the writable
attribute) and it's unclear whether is also applies to accessor properties. But
I am fine to land this CL as it is even without a clarification on this part.

[arv (Not doing code reviews), 2012/11/06 18:49:43]

I had a hard time finding this too. I even filed an ES6 bug before Allen pointed
out where to find this.

https://bugs.ecmascript.org/show_bug.cgi?id=931

+assertTrue(setSizeDescriptor.configurable);
+
+var s = new Set();
+assertFalse(s.hasOwnProperty('size'));
+for (var i = 0; i < 10; i++) {
+  assertEquals(i, s.size);
+  s.add(i);
+}
+for (var i = 9; i >= 0; i--) {
+  s.delete(i);
+  assertEquals(i, s.size);
+}
+
+
+var mapSizeDescriptor = Object.getOwnPropertyDescriptor(Map.prototype, 'size');
+assertEquals(undefined, mapSizeDescriptor.value);
+assertEquals(undefined, mapSizeDescriptor.set);
+assertTrue(mapSizeDescriptor.get instanceof Function);
+assertFalse(mapSizeDescriptor.enumerable);

[Michael Starzinger, 2012/11/06 09:32:40]

Likewise.

+assertTrue(mapSizeDescriptor.configurable);
+
+var m = new Map();
+assertFalse(m.hasOwnProperty('size'));
+for (var i = 0; i < 10; i++) {
+  assertEquals(i, m.size);
+  m.set(i, i);
+}
+for (var i = 9; i >= 0; i--) {
+  m.delete(i);
+  assertEquals(i, m.size);
+}