[es6] implement destructuring assignment [clean diff]

test/mjsunit/harmony/destructuring-assignment.js

+// Copyright 2015 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-destructuring-assignment --harmony-sloppy
+//
+
+function TestBasics() {
+  var a = {}, b, c, value = { a: "alpha", b: "beta", c: "gamma" };
+  assertEquals({a: a.str1} = {b: a.str2} = {c: a.str3} = {b, c} = value, value);
+  assertEquals(a, {str1: "alpha", str2: "beta", str3: "gamma"});
+  assertEquals(b, "beta");
+  assertEquals(c, "gamma");
+
+  assertEquals([a.str1, ,...c] = [, b] = "☕✌♥♫♪★", "☕✌♥♫♪★");
+  assertEquals(a.str1, "☕");
+  assertEquals(b, "✌");
+  assertEquals(c, ["♥", "♫", "♪", "★"]);
+
+  // Super-properties used
+  var bs = {};
+  class SuperClass {
+    get verbose() { return bs.verbose; }
+    set verbose(v) { bs.verboseSet = true; bs.verbose = v; }
+    get warningsAsErrors() { return bs.warningsAsErrors; }
+    set warningsAsErrors(v) {
+      bs.warningsAsErrorsSet = true;
+      bs.warningsAsErrors = v;
+    }
+    get entries() { return bs.entries; }
+    set entries(v) { bs.entriesSet = true; bs.entries = v; }
+  }
+  class ChildClass extends SuperClass {
+    constructor(O) {
+      super();
+      ({
+        verbose: super.verbose = false,
+        warningsAsErrors: super.warningsAsErrors = false,
+        entries: [...super.entries]
+      } = O || { entries: [] });
+    }
+  };
+  var childClass = new ChildClass({
+    warningsAsErrors: true,
+    entries: [1, 2, 3]
+  });
+  assertEquals(childClass.verbose, false);
+  assertEquals(childClass.warningsAsErrors, true);
+  assertEquals(childClass.entries, [1, 2, 3]);
+  assertEquals({ verboseSet: true, verbose: false,
+                 warningsAsErrorsSet: true, warningsAsErrors: true,
+                 entriesSet: true, entries: [1, 2, 3] }, bs);
+}
+TestBasics();