lepu-test-platform-web/node_modules/babel-plugin-transform-es20.../README.md

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# babel-plugin-transform-es2015-classes
> Compile ES2015 classes to ES5
## Caveats
Built-in classes such as `Date`, `Array`, `DOM` etc cannot be properly subclassed
due to limitations in ES5 (for the [es2015-classes](http://babeljs.io/docs/plugins/transform-es2015-classes) plugin).
You can try to use [babel-plugin-transform-builtin-extend](https://github.com/loganfsmyth/babel-plugin-transform-builtin-extend) based on `Object.setPrototypeOf` and `Reflect.construct`, but it also has some limitations.
## Installation
```sh
npm install --save-dev babel-plugin-transform-es2015-classes
```
## Usage
### Via `.babelrc` (Recommended)
**.babelrc**
```js
// without options
{
"plugins": ["transform-es2015-classes"]
}
// with options
{
"plugins": [
["transform-es2015-classes", {
"loose": true
}]
]
}
```
### Via CLI
```sh
babel --plugins transform-es2015-classes script.js
```
### Via Node API
```javascript
require("babel-core").transform("code", {
plugins: ["transform-es2015-classes"]
});
```
## Options
### `loose`
`boolean`, defaults to `false`.
#### Method enumerability
Please note that in loose mode class methods **are** enumerable. This is not in line
with the spec and you may run into issues.
#### Method assignment
Under loose mode, methods are defined on the class prototype with simple assignments
instead of being defined. This can result in the following not working:
```javascript
class Foo {
set bar() {
throw new Error("foo!");
}
}
class Bar extends Foo {
bar() {
// will throw an error when this method is defined
}
}
```
When `Bar.prototype.foo` is defined it triggers the setter on `Foo`. This is a
case that is very unlikely to appear in production code however it's something
to keep in mind.