99 lines
2.3 KiB
Markdown
99 lines
2.3 KiB
Markdown
# 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.
|