`React.createRef()` polyfill for React < 16.3

Install
=======

```sh
npm install react-create-ref --save
```

Use
===

Calls native `React.createRef()` if it's available (React >= 16.3), calls the polyfill function otherwise (React < 16.3).

```js
import createRef from 'react-create-ref'

class Example extends React.Component {
  constructor() {
    this.input = createRef()
  }

  render() {
    return (
      <form>
        <input type="text" ref={this.input} />
        <button type="button" onClick={() => this.input.current.focus()} />
      </form>
    )
  }
}
```