jquery-infinite-scroll-helper

jQuery Infinite Scroll Helper
=============================

A lightweight implementation of the infinite scroll mechanic. By providing two essential callbacks, loadMore and doneLoading, the jQuery Infinite Scroll Helper plugin makes it a breeze to add infinite scrolling functionality to your page.

Options
-------

$3

_(number)_ The number of pixels from the bottom of the window in which the loadMore callback should be invoked. The default is 0.

$3

_(number)_ The interval, in milliseconds, that the scroll event handler will be debounced.

$3

_(function)_ A callback that must return true or false, signaling whether loading has completed. This callback is passed a pageCount argument.

$3

_(number)_ The interval, in milliseconds, that the doneLoading callback will be called by the plugin. It will stop being called once it returns true. The default is 300.

$3

_(string)_ The class that will be added to the target element once loadMore has been invoked. The default is loading.

$3

_(string)_ A selector targeting the element that will receive the class specified by the loadingClass option.

$3

_(function)_ A callback function that is invoked when the scrollbar eclipses the bottom threshold of the element being scrolled. This callback is passed two arguments:

* pageCount: The page number to loaded. This can be helpful when making requests to endpoints that require a page number.
* done: A callback function that should be called when loading has completed. This is an alternative way to signal that you are done loading instead of defining the doneLoading callback.

$3

_(number)_ The amount of time, in milliseconds, before the loadMore callback is invoked once the bottom of the scroll container has been reached.

$3

_(string|HTMLElement)_ If provided, the element that the scroll listener will be attached to. This can either be a selector or a DOM element reference.
If not specified, the plugin will try to find the first scrollable parent if the element itself is not scrollable.

$3

_(number)_ The starting page count that the plugin will increment each time the loadMore callback is invoked. The default is 1.

$3

_(boolean)_ Whether or not the plugin should make an initial call to the loadMore callback. This can be set to true if, for instance, you need to load the initial content asynchronously on page load.

Methods
-------

$3

Destroys the plugin instance, removing all internal listeners and nullifying any external references.

$(selector).infiniteScrollHelper('destroy');

Usage
------

$('#my-element-to-watch').infiniteScrollHelper({
loadMore: function(page) {
// load some data, parse some data
},

doneLoading: function() {
// return true if you are done doing your thing, false otherwise
return false;
}
});

or when using the done argument instead of the doneLoading callback

$('#my-element-to-watch').infiniteScrollHelper({
loadMore: function(page, done) {
// you should use the page argument to either select an anchor/href and load
// the contents of that url or make a call to an API that accepts a page number

var nextPageUrl = $('.pagination a').eq(page - 1).attr('href');

$.get(nextPageUrl, function(data) {
$(data).find('.items').appendTo('#my-element-to-watch');
// call the done callback to let the plugin know you are done loading
done();
});

// or an API perhaps
$.getJSON('http://myawesomeapi.com/data?p=' + page, function(data) {
// parse json data and create new html then append

done();
});
}
});

The plugin can also be instantiated using constructor invocation

new InfiniteScrollHelper($('#my-element-to-watch')[0], options);

#### IE6/7 Note ####
There will most likely be an issue with the scroll offset calculation when calling the plugin direclty on an element that is set to overflow: scroll-y in IE 6 & 7. In this case, it is best to wrap the children of the element in a container and call the plugin on this container instead.

Dependencies
------------

* jQuery 1.7.0+

Changelog
---------

$3

* Fixed issue where loading class would not be removed after calling the done callback synchronously.
* Removed jQuery plugin repo JSON file.
* Added .editorconfig file.

$3

* Added a scrollContainer option.
* Added unit tests.

$3

* Changed how the scrollable element is detected by accounting for overflow scroll OR auto.
* Fixed issue where position fixed elements would not trigger the loadMore callback when the window was scrolled past y0.

$3

* Updated bower.json homepage URL to point to Github page.

$3

* Added a loadMoreDelay option. This allows you to set a delay before the loadMore callback is invoked.
* Fixed issue where calling destroy before the plugin was instantiated would cause unintentional instantiation of plugin.
* Added plugin as package on Bower.

$3

* Fixed/added the ability to use the plugin on elements with overflow scroll. Previously the plugin only worked when the element being watched was scrolled within the window.
* A done argument is now passed to the loadMore callback. You can invoke this callback to signal that you are done loading content instead of defining the doneLoading callback option.
* Added the debounceInt option. The plugin now uses debouncing for the scroll event. You can specify the interval if you want it to be different than the default 100ms.
* Added a loadingClassTarget option.
* Added a startingPageCount option.
* Added a triggerInitialLoad option.

$3

* Fixed issue #4 - destroy method was not properly destroying instance which prevented another instance from being created

$3

* The doneLoading callback now receives pageCount as a parameter.

$3

* Changed details in manifest file.
* Doc updates.

$3

* Fixed manifest file keyword error.

$3

* Regenerated minified/production script to match development version.

$3

* Initial Release.

License
-------
Copyright (c) 2014 Expand The Room, LLC

Licensed under the MIT license.