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- # babel-plugin-transform-es2015-arrow-functions
- > Compile ES2015 arrow functions to ES5
- ## Example
- **In**
- ```javascript
- var a = () => {};
- var a = (b) => b;
- const double = [1,2,3].map((num) => num * 2);
- console.log(double); // [2,4,6]
- var bob = {
- _name: "Bob",
- _friends: ["Sally", "Tom"],
- printFriends() {
- this._friends.forEach(f =>
- console.log(this._name + " knows " + f));
- }
- };
- console.log(bob.printFriends());
- ```
- **Out**
- ```javascript
- var a = function a() {};
- var a = function a(b) {
- return b;
- };
- var double = [1, 2, 3].map(function (num) {
- return num * 2;
- });
- console.log(double); // [2,4,6]
- var bob = {
- _name: "Bob",
- _friends: ["Sally", "Tom"],
- printFriends: function printFriends() {
- var _this = this;
- this._friends.forEach(function (f) {
- return console.log(_this._name + " knows " + f);
- });
- }
- };
- console.log(bob.printFriends());
- ```
- [Try in REPL](http://babeljs.io/repl/#?evaluate=true&lineWrap=true&presets=es2015%2Ces2015-loose&experimental=false&loose=false&spec=false&code=var%20a%20%3D%20()%20%3D%3E%20%7B%7D%3B%0Avar%20a%20%3D%20(b)%20%3D%3E%20b%3B%0A%0Aconst%20double%20%3D%20%5B1%2C2%2C3%5D.map((num)%20%3D%3E%20num%20*%202)%3B%0Aconsole.log(double)%3B%20%2F%2F%20%5B2%2C4%2C6%5D%0A%0Avar%20bob%20%3D%20%7B%0A%20%20_name%3A%20%22Bob%22%2C%0A%20%20_friends%3A%20%5B%22Sally%22%2C%20%22Tom%22%5D%2C%0A%20%20printFriends()%20%7B%0A%20%20%20%20this._friends.forEach(f%20%3D%3E%0A%20%20%20%20%20%20console.log(this._name%20%2B%20%22%20knows%20%22%20%2B%20f))%3B%0A%20%20%7D%0A%7D%3B%0Aconsole.log(bob.printFriends())%3B&playground=true)
- ## Installation
- ```sh
- npm install --save-dev babel-plugin-transform-es2015-arrow-functions
- ```
- ## Usage
- ### Via `.babelrc` (Recommended)
- **.babelrc**
- ```js
- // without options
- {
- "plugins": ["transform-es2015-arrow-functions"]
- }
- // with options
- {
- "plugins": [
- ["transform-es2015-arrow-functions", { "spec": true }]
- ]
- }
- ```
- ### Via CLI
- ```sh
- babel --plugins transform-es2015-arrow-functions script.js
- ```
- ### Via Node API
- ```javascript
- require("babel-core").transform("code", {
- plugins: ["transform-es2015-arrow-functions"]
- });
- ```
- ## Options
- * `spec` - This option wraps the generated function in `.bind(this)` and keeps uses of `this` inside the function as-is, instead of using a renamed `this`. It also adds a runtime check to ensure the functions are not instantiated.
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