# b-tween
A simple but powerful tweening engine for Javascript.

## Install

```bash
npm i b-tween
```

## Usage

#### ES Module

```js
import BTween from 'b-tween';
const tween = new BTween({
  from: {
    left: 0
  },
  to: {
    left: 700
  },
  duration: 500,
  easing: 'bounceOut',
  onUpdate: (keys) => {
    // You can do everything with keys
    block.style.left = keys.left + 'px';
  }
});
tween.start();
```

#### Commonjs

```js
const BTween = require('b-tween');
...
```

#### Browser

https://unpkg.com/b-tween/dist/b-tween.umd.js

```html
<script src="https://unpkg.com/b-tween/dist/b-tween.umd.js"></script>
<script>
  const tween = new BTween({
    ...
  });
  tween.start();
</script>
```

## Api

### new Tween(options)

#### options.from (object)

#### options.to (object)

#### options.duration (number)

#### options.delay (number)

#### options.easing (string)

* linear
* quadIn
* quadOut
* quadInOut
* cubicIn
* cubicOut
* cubicInOut
* quartIn
* quartOut
* quartInOut
* quintIn
* quintOut
* quintInOut
* sineIn
* sineOut
* sineInOut
* bounceIn
* bounceOut
* bounceInOut

#### options.onStart ( function(keys) {} )

#### options.onUpdate ( function(keys) {} )

#### options.onFinish ( function(keys) {} )

### Start Animation

```js
const tween = new Btween({...});
tween.start();
```

## LICENSE

[MIT](./LICENSE) © [PengJiyuan](https://github.com/PengJiyuan)