# when-dom-ready

> $(document).ready() for the 21st century

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Returns a Promise for cleaner usage, provides a Promise chain helper function and can also be used as a pure function. The Promise will resolve instantly if the DOM is already ready.

## Browser Compatibility

- IE9+ (requires Promise polyfill)
- Edge *
- Firefox 29+
- Safari 8+
- Chrome 33+
- Opera 23+

## Install

```shell
npm install --save when-dom-ready
```

or for quick testing:

```html
<script src="https://unpkg.com/when-dom-ready"></script>
```

## Usage

```js
import whenDomReady from 'when-dom-ready';

whenDomReady().then(() => console.log('DOM is ready yo!'));
```

You can still use callbacks if you want to:

```js
whenDomReady(() => console.log('DOM is ready yo!'));
```

## Promise chain helper

There is also a little helper function, `whenDomReady.resume()`, that pauses the execution of a Promise chain and then resumes it with the last value once the DOM is ready.

This allows you to specify complex async control flow in simple readable code:

```js
fetch('/my-badass-api.json')
  .then(getSomeProcessingDoneWhileWaitingForDom)
  .then(whenDomReady.resume())
  .then(injectDataIntoDom);
```

## Pure usage

You can make the function pure by passing in a `document` object. This is really [useful for tests](https://github.com/lukechilds/when-dom-ready/blob/master/test/unit.js) and mocking environments.

For example this works in Node.js:

```js
const Window = require('window');
const whenDomReady = require('when-dom-ready');

const { document } = new Window();

whenDomReady(document).then(() => console.log('DOM is ready yo!'));
```

Again, you can use the callback version as a pure function too:

```js
whenDomReady(() => console.log('DOM is ready yo!'), document);
```

And of course the helper:

```js
//...
  .then(whenDomReady.resume(document))
```

## License

MIT © Luke Childs