[es6] implement destructuring assignment

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-destructuring-bind
+
+// script-level tests
+var ox, oy = {}, oz;
+({
+  x: ox,
+  y: oy.value,
+  y2: oy["value2"],
+  z: ({ set v(val) { oz = val; } }).v
+} = {
+  x: "value of x",
+  y: "value of y1",
+  y2: "value of y2",
+  z: "value of z"
+});
+assertEquals("value of x", ox);
+assertEquals("value of y1", oy.value);
+assertEquals("value of y2", oy.value2);
+assertEquals("value of z", oz);
+
+[ox, oy.value, oy["value2"], ...{ set v(val) { oz = val; } }.v] = [
+  1007,
+  798432,
+  555,
+  1, 2, 3, 4, 5
+];
+assertEquals(ox, 1007);
+assertEquals(oy.value, 798432);
+assertEquals(oy.value2, 555);
+assertEquals(oz, [1, 2, 3, 4, 5]);
+
+
+(function testInFunction() {
+  var x, y = {}, z;
+  ({
+    x: x,
+    y: y.value,
+    y2: y["value2"],
+    z: ({ set v(val) { z = val; } }).v
+  } = {
+    x: "value of x",
+    y: "value of y1",
+    y2: "value of y2",
+    z: "value of z"
+  });
+  assertEquals("value of x", x);
+  assertEquals("value of y1", y.value);
+  assertEquals("value of y2", y.value2);
+  assertEquals("value of z", z);
+
+  [x, y.value, y["value2"], ...{ set v(val) { z = val; } }.v] = [
+    1007,
+    798432,
+    555,
+    1, 2, 3, 4, 5
+  ];
+  assertEquals(x, 1007);
+  assertEquals(y.value, 798432);
+  assertEquals(y.value2, 555);
+  assertEquals(z, [1, 2, 3, 4, 5]);
+})();
+
+
+(function testArrowFunctionInitializers() {
+  var fn = (config = { value: defaults.value } = { value: "BLAH" }) => config;
+  var defaults = {};
+  assertEquals({ value: "BLAH" }, fn());
+  assertEquals("BLAH", defaults.value);
+})();
+
+
+(function testArrowFunctionInitializers2() {
+  var fn = (config = [defaults.value] = ["BLAH"]) => config;
+  var defaults = {};
+  assertEquals(["BLAH"], fn());
+  assertEquals("BLAH", defaults.value);
+})();
+
+
+(function testFunctionInitializers() {
+  function fn(config = { value: defaults.value } = { value: "BLAH" }) {
+    return config;
+  }
+  var defaults = {};
+  assertEquals({ value: "BLAH" }, fn());
+  assertEquals("BLAH", defaults.value);
+})();
+
+
+(function testFunctionInitializers2() {
+  function fn(config = [defaults.value] = ["BLAH"]) { return config; }
+  var defaults = {};
+  assertEquals(["BLAH"], fn());
+  assertEquals("BLAH", defaults.value);
+})();
+
+
+(function testDeclarationInitializers() {
+  var defaults = {};
+  var { value } = { value: defaults.value } = { value: "BLAH" };
+  assertEquals("BLAH", value);
+  assertEquals("BLAH", defaults.value);
+})();
+
+
+(function testDeclarationInitializers2() {
+  var defaults = {};
+  var [value] = [defaults.value] = ["BLAH"];
+  assertEquals("BLAH", value);
+  assertEquals("BLAH", defaults.value);
+})();
+
+
+(function testObjectLiteralProperty() {
+  var ext = {};
+  var obj = {
+    a: { b: ext.b, c: ext["c"], d: { set v(val) { ext.d = val; } }.v } = {
+      b: "b", c: "c", d: "d" }
+  };
+  assertEquals({ b: "b", c: "c", d: "d" }, ext);
+  assertEquals({ a: { b: "b", c: "c", d: "d" } }, obj);
+})();
+
+
+(function testArrayLiteralProperty() {
+  var ext = {};
+  var obj = [
+    ...[ ext.b, ext["c"], { set v(val) { ext.d = val; } }.v ] = [
+      "b", "c", "d" ]
+  ];
+  assertEquals({ b: "b", c: "c", d: "d" }, ext);
+  assertEquals([ "b", "c", "d" ], obj);
+})();
+
+
+// TODO(caitp): add similar test for ArrayPatterns, once Proxies support
+// delegating symbol-keyed get/set.
+(function testObjectPatternOperationOrder() {
+  var steps = [];
+  var store = {};
+  function computePropertyName(name) {
+    steps.push("compute name: " + name);
+    return name;
+  }
+  function loadValue(descr, value) {
+    steps.push("load: " + descr + " > " + value);
+    return value;
+  }
+  function storeValue(descr, name, value) {
+    steps.push("store: " + descr + " = " + value);
+    store[name] = value;
+  }
+  var result = {
+    get a() { assertUnreachable(); },
+    set a(value) { storeValue("result.a", "a", value); },
+    get b() { assertUnreachable(); },
+    set b(value) { storeValue("result.b", "b", value); }
+  };
+
+  ({
+    obj: {
+      x: result.a = 10,
+      [computePropertyName("y")]: result.b = false,
+    } = {}
+  } = { obj: {
+    get x() { return loadValue(".temp.obj.x", undefined); },
+    set x(value) { assertUnreachable(); },
+    get y() { return loadValue(".temp.obj.y", undefined); },
+    set y(value) { assertUnreachable(); }
+  }});
+
+  assertPropertiesEqual({
+    a: 10,
+    b: false
+  }, store);
+
+  assertArrayEquals([
+    "load: .temp.obj.x > undefined",
+    "store: result.a = 10",
+
+    "compute name: y",
+    "load: .temp.obj.y > undefined",
+    "store: result.b = false"
+  ], steps);
+
+  steps = [];
+
+  ({
+    obj: {
+      x: result.a = 50,
+      [computePropertyName("y")]: result.b = "hello",
+    } = {}
+  } = { obj: {
+    get x() { return loadValue(".temp.obj.x", 20); },
+    set x(value) { assertUnreachable(); },
+    get y() { return loadValue(".temp.obj.y", true); },
+    set y(value) { assertUnreachable(); }
+  }});
+
+  assertPropertiesEqual({
+    a: 20,
+    b: true
+  }, store);
+
+  assertArrayEquals([
+    "load: .temp.obj.x > 20",
+    "store: result.a = 20",
+    "compute name: y",
+    "load: .temp.obj.y > true",
+    "store: result.b = true",
+  ], steps);
+})();