angular-scroll/README.md

angular-scroll
==============

Angular is only dependency (no jQuery). 8K minified or 2K gzipped.

Example
-------
Check out [the live demo](http://oblador.github.io/angular-scroll/) or the [source code](https://github.com/oblador/angular-scroll/blob/master/example/index.html).

Install
-------

#### With bower:

    $ bower install angular-scroll

#### With npm (for use with browserify):

    $ npm install angular-scroll

You can also download the [production version](https://raw.github.com/oblador/angular-scroll/master/angular-scroll.min.js) or the [development version](https://raw.github.com/oblador/angular-scroll/master/angular-scroll.js).

If you prefer a CDN hosted version (which might speed up your load times), check out [cdnjs.com/libraries/angular-scroll](https://cdnjs.com/libraries/angular-scroll).


Don't forget to add `duScroll` to your module dependencies. 

`angular.element` Scroll API
----------------------------

This module extends the `angular.element` object with a few jQuery like functions. Note that `$document` is an `angular.element`, for usage example see below. In case of name collisions existing jQuery or jqlite functions will be preserved, just use the prefixed version: ie `.duScrollTo()` instead of `.scrollTo()`.

#### `.scrollTo( left, top [, duration [, easing ] ] )`
Scrolls the element/window to the specified left/top position. If `duration` is specified the scrolling is animated for n milliseconds. If `easing` is ommited the animation will default to the `duScrollEasing` function.

#### `.scrollTo( element [, offset, [, duration [, easing ] ] ] )`
Alias of `.scrollToElement`.

#### `.scrollToElement( element [, offset, [, duration [, easing ] ] ] )`
Scrolls to the specified element, if `offset` is passed it will be subtracted from the elements position which is good if one uses floating menus. 

#### `.scrollToElementAnimated( element [, offset, [, duration [, easing ] ] ] )`
Convenience function. Works exactly the same as `scrollToElement` but uses the default values from `duScrollOffset`, `duScrollDuration` and `duScrollEasing` unless otherwise specified. 

#### `.scrollTop|scrollLeft( )`
Returns current scroll position. 

#### `.scrollTop|scrollLeft( top [, duration [, easing ] ] )` 
Scrolls to specified position in either axis, with optional animation. 

#### `.scrollTopAnimated|scrollLeftAnimated( top [, duration [, easing ] ] )` 
Convenience function like `scrollToElementAnimated` but for `scrollTop`/`scrollLeft`. 

#### Promises
Animated scrolling returns a `$q` promise, it will resolve when the scrolling has finished or be rejected if cancelled (by starting another scroll animation before it finished).

#### Example
```js
angular.module('myApp', ['duScroll']).
  controller('myCtrl', function($scope, $document) {
    var top = 400;
    var duration = 2000; //milliseconds

    //Scroll to the exact position
    $document.scrollTop(top, duration).then(function() {
      console && console.log('You just scrolled to the top!');
    });

    var offset = 30; //pixels; adjust for floating menu, context etc
    //Scroll to #some-id with 30 px "padding"
    //Note: Use this in a directive, not with document.getElementById 
    var someElement = angular.element(document.getElementById('some-id'));
    $document.scrollToElement(someElement, offset, duration);
  }
);
```

The above example can be achieved by configuration instead of arguments:

```js
angular.module('myApp', ['duScroll'])
  .value('duScrollDuration', 2000)
  .value('duScrollOffset', 30)
  .controller('myCtrl', function($scope, $document) {
    $document.scrollTopAnimated(400).then(function() {
      console && console.log('You just scrolled to the top!');
    });

    var someElement = angular.element(document.getElementById('some-id'));
    $document.scrollToElementAnimated(someElement);
  }
);
```


Directives
----------

### `du-smooth-scroll`
Provides smooth anchor scrolling. 
```html
<a href="#anchor" du-smooth-scroll>Scroll it!</a>
```

If you, for some reason, do not want to use the `href` attribute as fallback, just use the `du-smooth-scroll` attribute instead but without leading #. Example: `<a du-smooth-scroll="anchor">`.

### `du-scrollspy`
Observes whether the target element is at the top of the viewport (or container) and adds an `active` class if so. Takes optional `offset` and `duration` attributes which is passed on to `.scrollTo`,

```html
<a href="#anchor" du-scrollspy>Am i active?</a>
```

or together with Bootstrap

```html
<ul class="nav navbar-nav">
  <li du-scrollspy="anchor"><a href="#anchor">Link</a></li>
</ul>
```

### `du-spy-context`
Enables multiple sets of spies on the same target element. Takes optional `offset` attribute to 

```html
<ul du-spy-context class="nav navbar-nav">
  <li du-scrollspy="anchor"><a href="#anchor">Link</a></li>
</ul>
<ul du-spy-context class="nav navbar-nav">
  <li du-scrollspy="anchor"><a href="#anchor">Link</a></li>
</ul>
```
### `du-scroll-container`
Modifies behavior of `du-scrollspy` and `du-smooth-scroll` to observe/scroll within and element instead of the window/document. Good for modals/elements with `overflow: auto/scroll`.

```html
<div du-scroll-container>
  <p id="top">This is the top</p>
  <p id="anchor">Scroll to me, or <a href="#top" du-smooth-scroll>the top</a></p>
</div>
```

If your links lie outside of the scrollable element, wrap them with the `du-scroll-container` directive and send the element id as argument:

```html
<ul du-scroll-container="scroll-container">
  <li><a href="#anchor" du-smooth-scroll>Link</a></li>
</ul>
<div id="scroll-container">
  [...]
</div>
```

### [All in together now](http://www.youtube.com/watch?v=cx4KtTezEFg&feature=kp)
The directives play well together, try [the demo](http://oblador.github.io/angular-scroll/container.html) or inspect its [source code](https://github.com/oblador/angular-scroll/blob/master/example/container.html).

```html
<ul du-spy-context du-scroll-container="scroll-container">
  <li><a href="#anchor" offset="30" du-smooth-scroll du-scrollspy>Link</a></li>
</ul>
<ul du-spy-context du-scroll-container="scroll-container">
  <li><a href="#anchor" offset="30" du-smooth-scroll du-scrollspy>Link</a></li>
</ul>
<div id="scroll-container">
  [...]
</div>
```

Observing Scroll Position
-------------------------

**NOTE:** the `$duScrollChanged` event and the `scrollPosition` service are deprecated. Use `angular.element().on()` together with `.scrollTop()` instead. 

```js
angular.module('myApp', ['duScroll']).
  controller('MyCtrl', function($scope, $document){
    $document.on('scroll', function() {
      console.log('Document scrolled to ', $document.scrollLeft(), $document.scrollTop());
    });
    var container = angular.element(document.getElementById('container'));
    container.on('scroll', function() {
      console.log('Container scrolled to ', container.scrollLeft(), container.scrollTop());
    });
  }
);
```

Configuration
-------------

### Scroll speed
Duration is defined in milliseconds.

To set a scroll duration on a single anchor:
```html
<a href="#anchor" du-smooth-scroll duration="5000">Scroll it!</a>
```

To change the default duration:
```js
angular.module('myApp', ['duScroll']).value('duScrollDuration', 5000);
```

### Scroll easing
Set the `duScrollEasing` value to a function that takes and returns a value between 0 to 1. Here's [a few examples](https://gist.github.com/gre/1650294) to choose from.

```js
function invertedEasingFunction(x) {
  return 1-x;
}
angular.module('myApp', ['duScroll']).value('duScrollEasing', invertedEasingFunction);
```

You can also pass a custom easing function as the fourth argument in `scrollTo`.

### Debounce Scroll Events
Set the `duScrollSpyWait` value in milliseconds to debounce the handler and prevent it from triggering frequent events and increase performance for large pages and/or navigations with expanding nodes.

```js
angular.module('myApp', ['duScroll']).value('duScrollSpyWait', 1000);
```

### Greedy option
Set the `duScrollGreedy` value to `true` if the elements you are observing are not wrapping the whole section you want to observe, but merely the first one in the section (such as headlines).

```js
angular.module('myApp', ['duScroll']).value('duScrollGreedy', true);
```

### Offset
To change default offset (in pixels) for the `du-smooth-scroll` directive:

```js
angular.module('myApp', ['duScroll']).value('duScrollOffset', 30);
```

### When to cancel scroll animation
Specify on which events on the container the scroll animation should be cancelled by modifying `duScrollCancelOnEvents`, set to `false` to disable entirely as shown below. Defaults to `scroll mousedown mousewheel touchmove keydown`.

```js
angular.module('myApp', ['duScroll']).value('duScrollCancelOnEvents', false);
```

### Bottom spy
To make the last `du-scrollspy` link active when scroll reaches page/container bottom:

```js
angular.module('myApp', ['duScroll']).value('duScrollBottomSpy', true);
```

### Active class
Specify the active class name to apply to a link when it is active, default is `active`.

```js
angular.module('myApp', ['duScroll']).value('duScrollActiveClass', 'custom-class');
```

Events
------

The `duScrollspy` directive fires the global events `duScrollspy:becameActive` and `duScrollspy:becameInactive` with an angular.element wrapped element as first argument and the element being spied on as second. This is nice to have if you want the URL bar to reflect where on the page the visitor are, like this: 

```js
angular.module('myApp', ['duScroll']).
  run(function($rootScope) {
    if(!window.history || !history.replaceState) {
      return;
    }
    $rootScope.$on('duScrollspy:becameActive', function($event, $element, $target){
      //Automaticly update location
      var hash = $element.prop('hash');
      if (hash) {
        history.replaceState(null, null, hash);
      }
    });
  });
```


Building
--------

    $ npm install
    $ bower install
    $ gulp

Tests
-----

### Unit tests

    $ npm test

### End to end tests

    $ npm run update-webdriver
    $ npm run protractor