LibJS: Implement computed properties in object expressions

Libraries/LibJS/Tests/object-basic.js

@@ -1,13 +1,27 @@
 load("test-common.js");
 
 try {
-    var o = { 1: 23, foo: "bar", "hello": "friends" };
+    var foo = "bar";
+    var computed = "computed"
+    var o = {
+        1: 23,
+        foo,
+        bar: "baz",
+        "hello": "friends",
+        [1 + 2]: 42,
+        ["I am a " + computed + " key"]: foo,
+        duplicate: "hello",
+        duplicate: "world"
+    };
     assert(o[1] === 23);
     assert(o["1"] === 23);
     assert(o.foo === "bar");
     assert(o["foo"] === "bar");
     assert(o.hello === "friends");
     assert(o["hello"] === "friends");
+    assert(o[3] === 42);
+    assert(o["I am a computed key"] === "bar");
+    assert(o.duplicate === "world");
     o.baz = "test";
     assert(o.baz === "test");
     assert(o["baz"] === "test");
@@ -31,6 +45,25 @@ try {
     assert(o2.catch === 1);
     assert(o2.break === 1);
 
+    var a;
+    var append = x => { a.push(x); };
+
+    a = [];
+    var o3 = {[append(1)]: 1, [append(2)]: 2, [append(3)]: 3}
+    assert(a.length === 3);
+    assert(a[0] === 1);
+    assert(a[1] === 2);
+    assert(a[2] === 3);
+    assert(o3.undefined === 3);
+
+    a = [];
+    var o4 = {"test": append(1), "test": append(2), "test": append(3)}
+    assert(a.length === 3);
+    assert(a[0] === 1);
+    assert(a[1] === 2);
+    assert(a[2] === 3);
+    assert(o4.test === undefined);
+
     console.log("PASS");
 } catch (e) {
     console.log("FAIL: " + e);