# decamelize [](https://travis-ci.org/sindresorhus/decamelize)
> Convert a camelized string into a lowercased one with a custom separator
> Example: `unicornRainbow` → `unicorn_rainbow`
## Install
```
$ npm install --save decamelize
```
## Usage
```js
const decamelize = require('decamelize');
decamelize('unicornRainbow');
//=> 'unicorn_rainbow'
decamelize('unicornRainbow', '-');
//=> 'unicorn-rainbow'
```
## API
### decamelize(input, [separator])
#### input
Type: `string`
#### separator
Type: `string`
Default: `_`
## Related
See [`camelcase`](https://github.com/sindresorhus/camelcase) for the inverse.
## License
MIT © [Sindre Sorhus](https://sindresorhus.com)