Implement array/object destructuring (#3305)
This patch implements the core functionality of destructuring patterns. Function argument/for in-of pattern are currently unsupported. JerryScript-DCO-1.0-Signed-off-by: Zoltan Herczeg zherczeg.u-szeged@partner.samsung.com JerryScript-DCO-1.0-Signed-off-by: Robert Fancsik frobert@inf.u-szeged.hu
This commit is contained in:
Robert Fancsik
committed by
Zoltan Herczeg
Zoltan Herczeg
parent
b4b55a67a2
commit
213544ae47
@@ -0,0 +1,224 @@
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// Copyright JS Foundation and other contributors, http://js.foundation
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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function checkSyntax (str) {
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try {
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eval (str);
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assert (false);
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} catch (e) {
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assert (e instanceof SyntaxError);
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}
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}
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function assertArrayEqual (actual, expected) {
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assert (actual.length === expected.length);
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for (var i = 0; i < actual.length; i++) {
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assert (actual[i] === expected[i]);
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}
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}
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function mustThrow (str) {
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try {
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eval (str);
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assert (false);
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} catch (e) {
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assert (e instanceof TypeError);
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}
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}
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checkSyntax ("var [a]");
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checkSyntax ("var [a, o.a]");
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checkSyntax ("var [a, ...b,]");
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checkSyntax ("var [a, ...b = 4]");
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checkSyntax ("var [a, ...[b] = 4]");
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checkSyntax ("var [let]");
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checkSyntax ("var [get = []");
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checkSyntax ("var [get : 5]");
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checkSyntax ("var [[a = {},]");
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checkSyntax ("let [a,a] = []");
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checkSyntax ("let [a, ...a] = []");
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checkSyntax ("const [a,a] = []");
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checkSyntax ("const [a, ...a] = []");
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checkSyntax ("[new Object()] = []");
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checkSyntax ("[Object()] = []");
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checkSyntax ("[(a, b, d, c)] = []");
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checkSyntax ("[super] = []");
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checkSyntax ("[this] = []");
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checkSyntax ("[()] = []");
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checkSyntax ("try { let [$] = $;");
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mustThrow ("var [a] = 4");
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mustThrow ("var [a] = 5");
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mustThrow ("var [a] = {}");
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mustThrow ("var [a] = { get [Symbol.iterator] () { throw new TypeError } }");
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mustThrow ("var [a] = { [Symbol.iterator] () {} }");
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mustThrow ("var [a] = { [Symbol.iterator] () { return {} } }");
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mustThrow ("var [a] = { [Symbol.iterator] () { return { next: 5 } } }");
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mustThrow ("var [a] = { [Symbol.iterator] () { return { next: 5 } } }");
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mustThrow ("var [a] = { [Symbol.iterator] () { return { get next() { throw new TypeError } } } }");
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mustThrow ("var [a] = { [Symbol.iterator] () { return { next () { } } } }");
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mustThrow ("var [a] = { [Symbol.iterator] () { return { next () { } } } }");
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mustThrow ("var [a] = { [Symbol.iterator] () { return { next () { return { get value () { throw new TypeError }}}}}}");
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mustThrow ("var [a] = { [Symbol.iterator] () { return { next () { return { get done () { throw new TypeError }}}}}}");
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// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment
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// Basic variable assignment
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(function () {
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var foo = ["one", "two", "three"];
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var [red, yellow, green] = foo;
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assert (red === "one");
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assert (yellow === "two");
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assert (green === "three");
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}) ();
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// Assignment separate from declaration
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(function () {
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var a, b;
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[a, b] = [1, 2];
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assert (a === 1);
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assert (b === 2);
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}) ();
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// Default values
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(function () {
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var a, b;
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[a = 5, b = 7] = [1];
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assert (a === 1);
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assert (b === 7);
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}) ();
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// Swapping variables
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(function () {
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var a = 1;
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var b = 3;
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[a, b] = [b, a];
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assert (a === 3);
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assert (b === 1);
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var arr = [1,2,3];
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[arr[2], arr[1]] = [arr[1], arr[2]];
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assertArrayEqual (arr, [1, 3, 2]);
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}) ();
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// Parsing an array returned from a function
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(function () {
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function f() {
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return [1, 2];
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}
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var a, b;
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[a, b] = f();
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assert (a === 1);
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assert (b === 2);
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}) ();
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// Ignoring some returned values
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(function () {
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function f() {
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return [1, 2, 3];
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}
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var a, b;
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[a, ,b] = f();
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assert (a === 1);
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assert (b === 3);
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}) ();
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// Ignoring some returned values
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(function () {
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var [a, ...b] = [1, 2, 3];
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assert (a === 1);
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assertArrayEqual (b, [2, 3]);
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}) ();
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// Unpacking values from a regular expression match
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(function () {
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function parseProtocol(url) {
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var parsedURL = /^(\w+)\:\/\/([^\/]+)\/(.*)$/.exec(url);
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if (!parsedURL) {
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return false;
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}
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var [, protocol, fullhost, fullpath] = parsedURL;
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return protocol;
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}
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assert (parseProtocol("https://developer.mozilla.org/en-US/Web/JavaScript") === "https");
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}) ();
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// Test inner patterns I.
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(function () {
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let [a, [b, [c = 4, d = 5]], [e] = [6]] = [1, [2, [3,undefined]]];
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assert (a === 1);
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assert (b === 2);
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assert (c === 3);
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assert (d === 5);
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assert (e === 6);
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}) ();
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// Test inner patterns II.
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(function () {
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var o = {};
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[a, b, c, o.a = 4, o.b, o.c = 3] = ["1", "2", "3", undefined, "8", "6"];
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assert (a === "1");
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assert (b === "2");
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assert (c === "3");
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assert (o.a === 4);
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assert (o.b === "8");
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assert (o.c === "6");
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}) ();
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// Test rest element I.
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(function () {
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var o = {};
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[...o.a] = ["1", "2", "3"];
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assertArrayEqual (o.a, ["1", "2", "3"]);
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}) ();
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// Test rest element II.
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(function () {
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[...[a,b,c]] = ["1", "2", "3"];
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assert (a === "1");
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assert (b === "2");
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assert (c === "3");
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}) ();
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// Test inner object pattern I.
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(function () {
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[{f : a, g : b}, , , ...[c, d, e]] = [{ f : "1", g : "2"}, 3, 4, 5, 6, 7];
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assert (a === "1");
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assert (b === "2");
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assert (c === 5);
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assert (d === 6);
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assert (e === 7);
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}) ();
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// Multiple declaration
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(function () {
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var [a] = [1], [b] = [2];
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assert (a === 1);
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assert (b === 2);
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}) ();
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@@ -0,0 +1,199 @@
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// Copyright JS Foundation and other contributors, http://js.foundation
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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function checkSyntax (str) {
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try {
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eval (str);
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assert (false);
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} catch (e) {
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assert (e instanceof SyntaxError);
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}
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}
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function mustThrow (str) {
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try {
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eval (str);
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assert (false);
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} catch (e) {
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assert (e instanceof TypeError);
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}
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}
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checkSyntax ("var {a}");
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checkSyntax ("var {a, o.a}");
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checkSyntax ("var {a, ...b}");
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checkSyntax ("var {a, ...b} = 4");
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checkSyntax ("var {a, ...[b] = 4}");
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checkSyntax ("var {a,,} = 4");
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checkSyntax ("var {a :} = 4");
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checkSyntax ("var {a : ,} = 4");
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checkSyntax ("var {a : ['foobar']} = 4");
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checkSyntax ("var {let}");
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checkSyntax ("var {get = []");
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checkSyntax ("var {get : 5}");
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checkSyntax ("var {[a = {},}");
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checkSyntax ("let {a,a} = []");
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checkSyntax ("let {a : b, b} = []");
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checkSyntax ("const {a,a} = []");
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checkSyntax ("const {a : b, b} = []");
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checkSyntax ("try { let {$} = $;");
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mustThrow ("var {a} = null");
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mustThrow ("var {a} = undefined");
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// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment
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// Basic assignment
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(function () {
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var o = {p: 42, q: true};
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var {p, q} = o;
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assert (p === 42);
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assert (q === true);
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}) ();
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// Assignment without declaration
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(function () {
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var a, b;
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({a, b} = {a: 1, b: 2});
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assert (a === 1);
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assert (b === 2);
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}) ();
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// Assigning to new variable names
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(function () {
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var o = {p: 42, q: true};
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var {p: foo, q: bar} = o;
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assert (foo === 42);
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assert (bar === true);
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}) ();
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// Default values
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(function () {
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var {a = 10, b = 5} = {a: 3};
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assert (a === 3);
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assert (b === 5);
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}) ();
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// Assigning to new variables names and providing default values
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(function () {
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var {a: aa = 10, b: bb = 5} = {a: 3};
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assert (aa === 3);
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assert (bb === 5);
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}) ();
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// Nested object and array destructuring
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(function () {
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const metadata = {
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title: 'Scratchpad',
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translations: [
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{
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locale: 'de',
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localization_tags: [],
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last_edit: '2014-04-14T08:43:37',
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url: '/de/docs/Tools/Scratchpad',
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title: 'JavaScript-Umgebung'
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}
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],
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url: '/en-US/docs/Tools/Scratchpad'
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};
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let {
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title: englishTitle, // rename
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translations: [
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{
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title: localeTitle, // rename
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},
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],
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} = metadata;
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assert (englishTitle === "Scratchpad");
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assert (localeTitle === "JavaScript-Umgebung");
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}) ();
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// Computed object property names and destructuring
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(function () {
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let key = 'z';
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let {[key]: foo} = {z: 'bar'};
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assert (foo === "bar");
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}) ();
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// Invalid JavaScript identifier as a property name
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(function () {
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const foo = { 'fizz-buzz': true };
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const { 'fizz-buzz': fizzBuzz } = foo;
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assert (fizzBuzz === true);
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}) ();
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// Combined Array and Object Destructuring
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(function () {
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const props = [
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{ id: 1, name: 'Fizz'},
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{ id: 2, name: 'Buzz'},
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{ id: 3, name: 'FizzBuzz'}
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];
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const [,, { name }] = props;
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assert (name === "FizzBuzz");
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}) ();
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// The prototype chain is looked up when the object is deconstructed
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(function () {
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var obj = {self: '123'};
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Object.getPrototypeOf(obj).prot = '456';
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const {self, prot} = obj;
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assert (self === '123');
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assert (prot === '456');
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}) ();
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// Test inner patterns I.
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(function () {
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var a,b,c,d,e;
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var o = { a : { b: 2 }, c: 1, d: { e: undefined } };
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var { e: { b : a } = { b : 2, a : 1}, d: { e: { b : e = 2} = { b } } } = o;
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assert (a === 2);
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assert (b === undefined);
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assert (c === undefined);
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assert (d === undefined);
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assert (e === 2);
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}) ();
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// Test inner patterns II.
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(function () {
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var a,b,c,d,e;
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var o = { a : [{ b : 2 ,}, d], e : 5 };
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var { a: [{b, c = 3}, d = 4], e } = o;
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assert (a === undefined);
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assert (b === 2);
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assert (c === 3);
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assert (d === 4);
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assert (e === 5);
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}) ();
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// Multiple declaration
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(function () {
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var {a} = {a : 1}, {b} = {b : 2};
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assert (a === 1);
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assert (b === 2);
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}) ();
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Block a user