lepu-test-platform-web/node_modules/babel-plugin-check-es2015-c.../README.md

60 lines
1.0 KiB
Markdown
Raw Normal View History

# babel-plugin-check-es2015-constants
Validate ES2015 constants (prevents reassignment of const variables).
## Example
**In**
```js
const a = 1;
a = 2;
```
**Out**
```bash
repl: "a" is read-only
1 | const a = 1;
> 2 | a = 2;
| ^
```
[Try in REPL](http://babeljs.io/repl/#?babili=false&evaluate=true&lineWrap=false&presets=es2015&experimental=false&loose=false&spec=false&code=const%20a%20%3D%201%3B%0Aa%20%3D%202%3B&playground=true)
## Installation
```sh
npm install --save-dev babel-plugin-check-es2015-constants
```
## Usage
### Via `.babelrc` (Recommended)
**.babelrc**
```json
{
"plugins": ["check-es2015-constants"]
}
```
### Via CLI
```sh
babel --plugins check-es2015-constants script.js
```
### Via Node API
```javascript
require("babel-core").transform("code", {
plugins: ["check-es2015-constants"]
});
```
## Note
This check will only validate consts. If you need it to compile down to `var` then you must also install and enable [`transform-es2015-block-scoping`](http://babeljs.io/docs/plugins/transform-es2015-block-scoping/).