feat(copyWithin): implement immutable Array#copyWithin

README.md

@@ -16,15 +16,15 @@ This library provide immutable version of each methods.
 
 | Native method: Return type               | `@immutable-array/*`                       |
 | ---------------------------------------- | ---------------------------------------- |
-| [`Array.prototype.copyWithin()`](https://developer.mozilla.org/ja/docs/Web/JavaScript/Reference/Global_Objects/Array/copyWithin): `Array`| `copyWithin()`: new `Array` |
-| [`Array.prototype.fill()`](https://developer.mozilla.org/ja/docs/Web/JavaScript/Reference/Global_Objects/Array/fill): `Array`| [`fill()`](packages/fill): new `Array` |
 | [`Array.prototype.pop()`](https://developer.mozilla.org/ja/docs/Web/JavaScript/Reference/Global_Objects/Array/pop): `any`| [`pop()`](packages/pop): new  `Array` |
 | [`Array.prototype.push()`](https://developer.mozilla.org/ja/docs/Web/JavaScript/Reference/Global_Objects/Array/push): `Number`| [`push()`](packages/push): new  `Array` |
 | [`Array.prototype.shift()`](https://developer.mozilla.org/ja/docs/Web/JavaScript/Reference/Global_Objects/Array/shift): `any`| [`shift()`](packages/shift): new  `Array` |
 | [`Array.prototype.unshift()`](https://developer.mozilla.org/ja/docs/Web/JavaScript/Reference/Global_Objects/Array/unshift): `any`| [`unshift()`](packages/unshift): new  `Array` |
 | [`Array.prototype.splice()`](https://developer.mozilla.org/ja/docs/Web/JavaScript/Reference/Global_Objects/Array/splice): `Array`| [`splice()`](packages/splice): new  `Array` |
 | [`Array.prototype.reverse()`](https://developer.mozilla.org/ja/docs/Web/JavaScript/Reference/Global_Objects/Array/reverse): `Array`| [`reverse()`](packages/sort): new `Array` |
 | [`Array.prototype.sort()`](https://developer.mozilla.org/ja/docs/Web/JavaScript/Reference/Global_Objects/Array/sort): `Array`| [`sort()`](packages/sort): new  `Array` |
+| [`Array.prototype.fill()`](https://developer.mozilla.org/ja/docs/Web/JavaScript/Reference/Global_Objects/Array/fill): `Array`| [`fill()`](packages/fill): new `Array` |
+| [`Array.prototype.copyWithin()`](https://developer.mozilla.org/ja/docs/Web/JavaScript/Reference/Global_Objects/Array/copyWithin): `Array`| [`copyWithin()`](packages/copy-within): new `Array` |
 
 
 ## Install

packages/copy-within/LICENSE

@@ -0,0 +1,19 @@
+Copyright (c) 2017 azu
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

packages/copy-within/README.md

@@ -0,0 +1,82 @@
+# @immutable-array/copy-within
+
+Immutable [`Array.prototype.copyWithin()`](https://developer.mozilla.org/ja/docs/Web/JavaScript/Reference/Global_Objects/Array/copyWithin).
+
+## Install
+
+Install with [npm](https://www.npmjs.com/):
+
+    npm install @immutable-array/copy-within
+
+## Usage
+
+Same API with [`Array.prototype.copyWithin()`](https://developer.mozilla.org/ja/docs/Web/JavaScript/Reference/Global_Objects/Array/copyWithin)
+
+```ts
+/**
+ * Returns the this object after copying a section of the array identified by start and end
+ * to the same array starting at position target
+ * @param array Base array
+ * @param target If target is negative, it is treated as length+target where length is the
+ * length of the array.
+ * @param start If start is negative, it is treated as length+start. If end is negative, it
+ * is treated as length+end.
+ * @param end If not specified, length of the this object is used as its default value.
+ */
+export declare function copyWithin<T>(array: Array<T>, target: number, start: number, end?: number): Array<T>;
+```
+
+## Example
+
+```js
+import { copyWithin } from "@immutable-array/copyWithin";
+const originalArray = [1, 2, 3, 4, 5];
+assert.deepStrictEqual(copyWithin(originalArray, -2), [1, 2, 3, 1, 2]);
+assert.deepStrictEqual(copyWithin(originalArray, 0, 3), [4, 5, 3, 4, 5]);
+assert.deepStrictEqual(copyWithin(originalArray, 0, 3, 4), [4, 2, 3, 4, 5]);
+assert.deepStrictEqual(copyWithin(originalArray, 0, -2, -1), [4, 2, 3, 4, 5]);
+```
+
+TODO: Array-like.
+
+This is not specified behavior.
+
+If you interesting in this, Please comment to [copyWithIn() with Array-like · Issue #20 · azu/immutable-array-prototype](https://github.com/azu/immutable-array-prototype/issues/20 "copyWithIn() with Array-like · Issue #20 · azu/immutable-array-prototype").
+
+```js
+import { copyWithin } from "@immutable-array/copyWithin";
+const arrayLike = { length: 5, 3: 1 };
+let actual = copyWithin(arrayLike, 0, 3);
+assert.deepStrictEqual(actual, [1, , , 1,]);
+```
+
+## Changelog
+
+See [Releases page](https://github.com/azu/immutable-array-prototype/releases).
+
+## Running tests
+
+Install devDependencies and Run `npm test`:
+
+    npm i -d && npm test
+
+## Contributing
+
+Pull requests and stars are always welcome.
+
+For bugs and feature requests, [please create an issue](https://github.com/azu/immutable-array-prototype/issues).
+
+1. Fork it!
+2. Create your feature branch: `git checkout -b my-new-feature`
+3. Commit your changes: `git commit -am 'Add some feature'`
+4. Push to the branch: `git push origin my-new-feature`
+5. Submit a pull request :D
+
+## Author
+
+- [github/azu](https://github.com/azu)
+- [twitter/azu_re](https://twitter.com/azu_re)
+
+## License
+
+MIT © azu

packages/copy-within/package.json

@@ -0,0 +1,39 @@
+{
+  "directories": {
+    "lib": "lib",
+    "test": "test"
+  },
+  "author": "azu",
+  "license": "MIT",
+  "files": [
+    "bin/",
+    "lib/",
+    "src/"
+  ],
+  "name": "@immutable-array/copy-within",
+  "version": "1.0.0",
+  "description": "Immutable Array.prototype.copyWithin().",
+  "main": "lib/copy-within.js",
+  "scripts": {
+    "build": "cross-env NODE_ENV=production tsc -p .",
+    "watch": "tsc -p . --watch",
+    "prepublish": "npm run --if-present build"
+  },
+  "keywords": [
+    "array",
+    "immutable"
+  ],
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/azu/immutable-array-prototype.git"
+  },
+  "bugs": {
+    "url": "https://github.com/azu/immutable-array-prototype/issues"
+  },
+  "homepage": "https://github.com/azu/immutable-array-prototype/tree/master/packages/copy-within/",
+  "devDependencies": {
+    "@types/node": "^8.0.2",
+    "cross-env": "^5.0.1",
+    "typescript": "^2.3.4"
+  }
+}

packages/copy-within/src/copy-within.ts

@@ -0,0 +1,13 @@
+/**
+ * Returns the this object after copying a section of the array identified by start and end
+ * to the same array starting at position target
+ * @param array Base array
+ * @param target If target is negative, it is treated as length+target where length is the
+ * length of the array.
+ * @param start If start is negative, it is treated as length+start. If end is negative, it
+ * is treated as length+end.
+ * @param end If not specified, length of the this object is used as its default value.
+ */
+export function copyWithin<T>(array: Array<T>, target: number, start: number, end: number = array.length): Array<T> {
+    return Array.prototype.slice.call(array).copyWithin(target, start, end);
+}

packages/copy-within/test/copy-within-test.ts

@@ -0,0 +1,35 @@
+// MIT © 2017 azu
+import * as assert from "assert";
+import { copyWithin } from "../src/copy-within";
+
+describe("copyWithin", () => {
+    it("should return immutable array", () => {
+        const originalArray = ["a", "b", "c", "d", "e"];
+        const resultArray = copyWithin(originalArray, 1);
+        assert.ok(originalArray !== resultArray);
+    });
+
+    it("can copyWithin empty array", () => {
+        const originalArray = [];
+        assert.deepStrictEqual(originalArray.copyWithin(0), []);
+    });
+
+    it("should be idempotent - x() === x()", () => {
+        const originalArray = ["a", "b", "c", "d", "e"];
+        assert.deepStrictEqual(originalArray.copyWithin(-2), originalArray.copyWithin(-2));
+    });
+
+    it("should work copyWithin", () => {
+        // https://developer.mozilla.org/ja/docs/Web/JavaScript/Reference/Global_Objects/Array/copyWithin
+        const originalArray = [1, 2, 3, 4, 5];
+        assert.deepStrictEqual(copyWithin(originalArray, -2), [1, 2, 3, 1, 2]);
+        assert.deepStrictEqual(copyWithin(originalArray, 0, 3), [4, 5, 3, 4, 5]);
+        assert.deepStrictEqual(copyWithin(originalArray, 0, 3, 4), [4, 2, 3, 4, 5]);
+        assert.deepStrictEqual(copyWithin(originalArray, 0, -2, -1), [4, 2, 3, 4, 5]);
+    });
+    it("should copyWithin to Array-like", () => {
+        const arrayLike = { length: 5, 3: 1 };
+        let actual = copyWithin(arrayLike, 0, 3);
+        assert.deepStrictEqual(actual, [1, , , 1]);
+    });
+});

packages/copy-within/tsconfig.json

@@ -0,0 +1,9 @@
+{
+  "extends": "../../tsconfig.json",
+  "compilerOptions": {
+    "outDir": "./lib/"
+  },
+  "include": [
+    "src/**/*"
+  ]
+}