src/ng/anchorScroll.js
'use strict';
/**
* @ngdoc provider
* @name $anchorScrollProvider
* @this
*
* @description
* Use `$anchorScrollProvider` to disable automatic scrolling whenever
* {@link ng.$location#hash $location.hash()} changes.
*/
function $AnchorScrollProvider() {
var autoScrollingEnabled = true;
/**
* @ngdoc method
* @name $anchorScrollProvider#disableAutoScrolling
*
* @description
* By default, {@link ng.$anchorScroll $anchorScroll()} will automatically detect changes to
* {@link ng.$location#hash $location.hash()} and scroll to the element matching the new hash.<br />
* Use this method to disable automatic scrolling.
*
* If automatic scrolling is disabled, one must explicitly call
* {@link ng.$anchorScroll $anchorScroll()} in order to scroll to the element related to the
* current hash.
*/
this.disableAutoScrolling = function() {
autoScrollingEnabled = false;
};
/**
* @ngdoc service
* @name $anchorScroll
* @kind function
* @requires $window
* @requires $location
* @requires $rootScope
*
* @description
* When called, it scrolls to the element related to the specified `hash` or (if omitted) to the
* current value of {@link ng.$location#hash $location.hash()}, according to the rules specified
* in the
* [HTML5 spec](http://www.w3.org/html/wg/drafts/html/master/browsers.html#an-indicated-part-of-the-document).
*
* It also watches the {@link ng.$location#hash $location.hash()} and automatically scrolls to
* match any anchor whenever it changes. This can be disabled by calling
* {@link ng.$anchorScrollProvider#disableAutoScrolling $anchorScrollProvider.disableAutoScrolling()}.
*
* Additionally, you can use its {@link ng.$anchorScroll#yOffset yOffset} property to specify a
* vertical scroll-offset (either fixed or dynamic).
*
* @param {string=} hash The hash specifying the element to scroll to. If omitted, the value of
* {@link ng.$location#hash $location.hash()} will be used.
*
* @property {(number|function|jqLite)} yOffset
* If set, specifies a vertical scroll-offset. This is often useful when there are fixed
* positioned elements at the top of the page, such as navbars, headers etc.
*
* `yOffset` can be specified in various ways:
* - **number**: A fixed number of pixels to be used as offset.<br /><br />
* - **function**: A getter function called everytime `$anchorScroll()` is executed. Must return
* a number representing the offset (in pixels).<br /><br />
* - **jqLite**: A jqLite/jQuery element to be used for specifying the offset. The distance from
* the top of the page to the element's bottom will be used as offset.<br />
* **Note**: The element will be taken into account only as long as its `position` is set to
* `fixed`. This option is useful, when dealing with responsive navbars/headers that adjust
* their height and/or positioning according to the viewport's size.
*
* <br />
* <div class="alert alert-warning">
* In order for `yOffset` to work properly, scrolling should take place on the document's root and
* not some child element.
* </div>
*
* @example
<example module="anchorScrollExample" name="anchor-scroll">
<file name="index.html">
<div id="scrollArea" ng-controller="ScrollController">
<a ng-click="gotoBottom()">Go to bottom</a>
<a id="bottom"></a> You're at the bottom!
</div>
</file>
<file name="script.js">
angular.module('anchorScrollExample', [])
.controller('ScrollController', ['$scope', '$location', '$anchorScroll',
function($scope, $location, $anchorScroll) {
$scope.gotoBottom = function() {
// set the location.hash to the id of
// the element you wish to scroll to.
$location.hash('bottom');
// call $anchorScroll()
$anchorScroll();
};
}]);
</file>
<file name="style.css">
#scrollArea {
height: 280px;
overflow: auto;
}
#bottom {
display: block;
margin-top: 2000px;
}
</file>
</example>
*
* <hr />
* The example below illustrates the use of a vertical scroll-offset (specified as a fixed value).
* See {@link ng.$anchorScroll#yOffset $anchorScroll.yOffset} for more details.
*
* @example
<example module="anchorScrollOffsetExample" name="anchor-scroll-offset">
<file name="index.html">
<div class="fixed-header" ng-controller="headerCtrl">
<a href="" ng-click="gotoAnchor(x)" ng-repeat="x in [1,2,3,4,5]">
Go to anchor {{x}}
</a>
</div>
<div id="anchor{{x}}" class="anchor" ng-repeat="x in [1,2,3,4,5]">
Anchor {{x}} of 5
</div>
</file>
<file name="script.js">
angular.module('anchorScrollOffsetExample', [])
.run(['$anchorScroll', function($anchorScroll) {
$anchorScroll.yOffset = 50; // always scroll by 50 extra pixels
}])
.controller('headerCtrl', ['$anchorScroll', '$location', '$scope',
function($anchorScroll, $location, $scope) {
$scope.gotoAnchor = function(x) {
var newHash = 'anchor' + x;
if ($location.hash() !== newHash) {
// set the $location.hash to `newHash` and
// $anchorScroll will automatically scroll to it
$location.hash('anchor' + x);
} else {
// call $anchorScroll() explicitly,
// since $location.hash hasn't changed
$anchorScroll();
}
};
}
]);
</file>
<file name="style.css">
body {
padding-top: 50px;
}
.anchor {
border: 2px dashed DarkOrchid;
padding: 10px 10px 200px 10px;
}
.fixed-header {
background-color: rgba(0, 0, 0, 0.2);
height: 50px;
position: fixed;
top: 0; left: 0; right: 0;
}
.fixed-header > a {
display: inline-block;
margin: 5px 15px;
}
</file>
</example>
*/
this.$get = ['$window', '$location', '$rootScope', function($window, $location, $rootScope) {
var document = $window.document;
// Helper function to get first anchor from a NodeList
// (using `Array#some()` instead of `angular#forEach()` since it's more performant
// and working in all supported browsers.)
function getFirstAnchor(list) {
var result = null;
Array.prototype.some.call(list, function(element) {
if (nodeName_(element) === 'a') {
result = element;
return true;
}
});
return result;
}
function getYOffset() {
var offset = scroll.yOffset;
if (isFunction(offset)) {
offset = offset();
} else if (isElement(offset)) {
var elem = offset[0];
var style = $window.getComputedStyle(elem);
if (style.position !== 'fixed') {
offset = 0;
} else {
offset = elem.getBoundingClientRect().bottom;
}
} else if (!isNumber(offset)) {
offset = 0;
}
return offset;
}
function scrollTo(elem) {
if (elem) {
elem.scrollIntoView();
var offset = getYOffset();
if (offset) {
// `offset` is the number of pixels we should scroll UP in order to align `elem` properly.
// This is true ONLY if the call to `elem.scrollIntoView()` initially aligns `elem` at the
// top of the viewport.
//
// IF the number of pixels from the top of `elem` to the end of the page's content is less
// than the height of the viewport, then `elem.scrollIntoView()` will align the `elem` some
// way down the page.
//
// This is often the case for elements near the bottom of the page.
//
// In such cases we do not need to scroll the whole `offset` up, just the difference between
// the top of the element and the offset, which is enough to align the top of `elem` at the
// desired position.
var elemTop = elem.getBoundingClientRect().top;
$window.scrollBy(0, elemTop - offset);
}
} else {
$window.scrollTo(0, 0);
}
}
function scroll(hash) {
// Allow numeric hashes
hash = isString(hash) ? hash : isNumber(hash) ? hash.toString() : $location.hash();
var elm;
// empty hash, scroll to the top of the page
if (!hash) scrollTo(null);
// element with given id
else if ((elm = document.getElementById(hash))) scrollTo(elm);
// first anchor with given name :-D
else if ((elm = getFirstAnchor(document.getElementsByName(hash)))) scrollTo(elm);
// no element and hash === 'top', scroll to the top of the page
else if (hash === 'top') scrollTo(null);
}
// does not scroll when user clicks on anchor link that is currently on
// (no url change, no $location.hash() change), browser native does scroll
if (autoScrollingEnabled) {
$rootScope.$watch(function autoScrollWatch() {return $location.hash();},
function autoScrollWatchAction(newVal, oldVal) {
// skip the initial scroll if $location.hash is empty
if (newVal === oldVal && newVal === '') return;
jqLiteDocumentLoaded(function() {
$rootScope.$evalAsync(scroll);
});
});
}
return scroll;
}];
}