Efx

Status

Efx is currently a WORK IN PROGRESS and not yet intended for production use.

Overview

Efx is a Javascript library designed to make it easy to implement effects through HTML 5 markup. At its root, it is based on the "trigger-target" paradigm whereby, when a user interacts with a trigger in a defined manner, an effect occurs on its target(s).

Motivation

The simplest example of an expandable content area:

<button data-target="element">Trigger</button>
<div id="element" data-effect="toggle">Target</div>

Parent-based resolution of an effect on a target:

<button data-target="element">Trigger</button>
<div data-effect="toggle">
    <div id="element">Target</div>
    <div>Not a target</div>
</div>

Selector-based resolution for expanding multiple content areas at once:

<button data-target=".element">Trigger</button>
<div data-effect="toggle">
    <div class="element">One target</div>
    <div>Not a target</div>
    <div class="element">Another target</div>
</div>

Dynamics

The Efx engine is implemented as a jQuery module.

Consequently, it can be initialized as:

$('#target').efx()

However, before initialization occurs, one or more drivers should be added.

$().efx('add', effect, event, driver)

The effect is a common name given to the effect, such as "expand". The event is a DOM event such as "click". The driver is a function that is initiated upon the event occurring.

While the engine manages the delegation of the trigger-target paradigm, it is the drivers that actually provide the effects functionality.

The general prototype for a driver function is:

function(data){

    var trigger   = data.trigger,
        target    = data.target,
        container = data.container;

    /* do something to the container, target and trigger */
}

In this prototype, trigger is the element that was clicked, target is the element that was directly targeted, and container is the element that defines the effect (which might be the same as target). All three are jQuery objects.

A simple expand effect on the click event might be implemented as:

$().efx('add', 'expand', 'click', function(data){

    var target    = data.target,
        trigger   = data.trigger;

    if(target.is(':hidden')){
        trigger.addClass('active');
        target.slideDown();
    }else{
        trigger.removeClass('active');
        target.slideUp();
    }

})

The engine also reserves a special init event that will fire when the Efx is first initialized on the element or a containing element.

Running with the expand example above, init might set the initial state of the trigger:

$().efx('add', 'expand', 'init', function(data){

    var target    = data.target,
        trigger   = data.trigger;

    if(target.is(':hidden')){
        trigger.addClass('active');
    }else{
        trigger.removeClass('active');
    }

})

For each event that invokes the engine, the engine will only invoke one effect callback per target. Resolution of the effect (and container) occurs by way of a closest ancestor search, meaning that an effect on the element itself takes precedence over its direct ancestor, its direct ancestor takes precedence over further ancestors, and so on.

In situations where multiple targets exist for a single trigger and the driver modifies trigger state, the driver must be careful not to modify the trigger's state multiple times.

It should also be noted that all drivers should be attached before Efx is initialized over element(s). Efx may be updated later in development to no longer impose this constraint.

Drivers

Toggle

The toggle driver provides the ability to designate a trigger that toggles the visibility on target(s). If a target is show, then it hides it, while if a target is hidden, then it shows it. This driver has no side-effects on the container or any of another elements besides the target.

The data-toggle attribute supports two visibility states on targets:

• show sets a target to be shown
• hide sets a target to be hidden

The hide visibility is the default behavior.

The data-toggle attribute also supports behavior states on the container:

• basic hides and shows the content without any effects.
• slide slides the content up and down rather than just showing and hiding it.
• fade fades the content in and out rather than just showing and hiding it.

The basic behavior is the default behavior.

If the target is also the container (the data-effect attribute is assigned directly on the target, then both a visibility and a behavior state may be specified at the same time.

A simple example:

<button data-target="element">Trigger</button>
<div id="element" data-effect="toggle">Target</div>

An example that starts with the content visible:

<button data-target="element">Trigger</button>
<div id="element" data-effect="toggle" data-toggle="show">Target</div>

An example that slides the content in and out rather than showing and hiding it, also starting with the content visible in this particular example:

<button data-target="element">Trigger</button>
<div id="element" data-effect="toggle" data-toggle="slide show">Target</div>

An example that fades the content in and out rather than showing and hiding it, also starting with the content visible in this particular example:

<button data-target="element">Trigger</button>
<div id="element" data-effect="toggle" data-toggle="fade show">Target</div>

Accordion

The accordion driver is similar to toggle in that it handles visibility. However, as opposed to toggle, the accordion driver hides all other targets in the data-effect="accordion" container. It will not, however, affect any elements that are not targets of data-effect, allowing one to specify other elements within the accordion that are not affected by the effect.

The data-accordion attribute supports two visibility states on targets:

• show sets a target to be shown
• hide sets a target to be hidden

The hide visibility is the default behavior.

The data-toggle attribute also supports behavior states on the container:

• basic simply hides and shows the content without any effects.
• slide slides the content up and down rather than just showing and hiding it. The slide effect simultaneously slides up any non-targeted contents while sliding down any targeted contents.
• fade fades the content in and out rather than just showing and hiding it. In this case, the non-targeted contents will be hidden without a fade, because otherwise this creates a jarring effect on the page layout.

The slide behavior is the default behavior.

A visibility and behavior state should not be specified on the same element, because a target should not also be the container. If a target is the same as a container, then the toggle driver should be used instead.

A simple example:

<div data-effect="accordion">
    <div data-target="element1">Trigger 1</div>
    <div id="element1">Target 1</div>
    <div data-target="element2">Trigger 2</div>
    <div id="element2">Target 2</div>
</div>

Triggers may also reside outside of the accordion container:

<div data-target="element1">Trigger 1</div>
<div data-target="element2">Trigger 2</div>
<div data-effect="accordion">
    <div id="element1">Target 1</div>
    <div id="element2">Target 2</div>
</div>

An example that slides the content in and out rather than showing and hiding it:

<div data-effect="accordion" data-accordion="slide">
    <div data-target="element1">Trigger 1</div>
    <div id="element1">Target 1</div>
    <div data-target="element2">Trigger 2</div>
    <div id="element2">Target 2</div>
</div>

An example that fades the content in and out rather than showing and hiding it:

<div data-effect="accordion" data-accordion="fade">
    <div data-target="element1">Trigger 1</div>
    <div id="element1">Target 1</div>
    <div data-target="element2">Trigger 2</div>
    <div id="element2">Target 2</div>
</div>

Tabs

The tabs driver is similar to toggle in that it handles visibility. However, as opposed to toggle, the tabs driver hides all other targets in the data-effect="tabs" container. It will not, however, affect any elements that are not targets of data-effect, allowing one to specify other elements within the tabs markup that are not affected by the effect.

The data-tabs attribute supports two visibility states on targets:

• show sets a target to be shown
• hide sets a target to be hidden

The hide visibility is the default behavior.

The data-toggle attribute also supports behavior states on the container:

• basic simply hides and shows the content without any effects.
• slide slides the content up and down rather than just showing and hiding it. The slide effect simultaneously slides up any non-targeted contents while sliding down any targeted contents.
• fade fades the content in and out rather than just showing and hiding it. In this case, the non-targeted contents will be hidden without a fade, because otherwise this creates a jarring effect on the page layout.

The fade behavior is the default behavior.

A visibility and behavior state should not be specified on the same element, because a target should not also be the container. If a target is the same as a container, then the toggle driver should be used instead.

A simple example:

<div data-target="element1">Trigger 1</div>
<div data-target="element2">Trigger 2</div>
<div data-effect="tabs">
    <div id="element1">Target 1</div>
    <div id="element2">Target 2</div>
</div>

Triggers may also reside within the tabs container:

<div data-effect="tabs">
    <div data-target="element1">Trigger 1</div>
    <div data-target="element2">Trigger 2</div>
    <div id="element1">Target 1</div>
    <div id="element2">Target 2</div>
</div>

An example that just hides/shows the content without fading it:

<div data-target="element1">Trigger 1</div>
<div data-target="element2">Trigger 2</div>
<div data-effect="tabs" data-tabs="basic">
    <div id="element1">Target 1</div>
    <div id="element2">Target 2</div>
</div>

An example that slides the content in and out rather than fading it:

<div data-target="element1">Trigger 1</div>
<div data-target="element2">Trigger 2</div>
<div data-effect="tabs" data-tabs="slide">
    <div id="element1">Target 1</div>
    <div id="element2">Target 2</div>
</div>

Development

Setup

Start by installing dependencies:

bundle
npm install

To run the tests, additionally run:

./node_modules/bower/bin/bower install

Compiling

The compilation of assets is handled via WebBlocks.

The default build includes only the engine (no different than copying src/engine.js):

bundle exec blocks build

To create a build with a driver:

bundle exec blocks build --include efx driver tabs

To create a build with multiple drivers:

bundle exec blocks build --include efx driver tabs, efx driver toggle

To add jQuery to this build:

bundle exec blocks build --include efx driver tabs, efx driver toggle, jquery

To create a build with all drivers (can add jQuery the same way as above):

bundle exec blocks build --include efx driver

Credits

Efx is written and maintained by Eric Bollens.

Efx is implemented as a jQuery module.

In unit tests, Efx uses the QUnit library.

In its demos, Efx uses Twitter Bootstrap and the jQuery Syntax Highlighter for presentational styles.

For compilation, Efx uses WebBlocks.

License

Efx is open-source software licensed under the BSD 3-clause license. The full text of the license may be found in the LICENSE file.