Animations with ngAnimate

Objectives

  • Use the ngAnimate module to add animations to an application.
  • Understand the properties that ngAnimate adds to directives.

Getting started

Angular supports animations on enter, leave, and move. This is achieved by loading the ngAnimate module, which will automatically add the ng-enter/ng-leave/ng-move classes to your object when it is added/removed.

Animations are only attached to elements that have the following directives:

Directive Supported Animations
ngRepeat enter, leave and move
ngView enter and leave
ngInclude enter and leave
ngSwitch enter and leave
ngIf enter and leave
ngClass add and remove (the CSS class(es) present)
ngShow & ngHide add and remove (the ng-hide class value)
form & ngModel add and remove (dirty, pristine, valid, invalid & all other validations)
ngMessages add and remove (ng-active & ng-inactive)
ngMessage enter and leave

Read the ngAnimate Documentation

Load angular-animate.js using a <script> tag. Place this in the <head></head> tags.

<script src="https://cdnjs.cloudflare.com/ajax/libs/angular.js/1.5.0/angular-animate.js"></script>

Inject the ngAnimate dependency into your module.

var app = angular.module('AnimationsApp', ['ngAnimate']);

Defining an animation class

To add an animation to an item simply add a class to that item and define a css animation that requires the item to have both your custom class and ng-enter/ng-leave/ng-move. There are also two additional classes with the -active postfix that you'll need to define, to represent the final state of the animation.

.myclass.ng-enter, .myclass.ng-move {
  //animation here
}

.myclass.ng-leave {
  //animation here
}

.myclass.ng-enter.ng-enter-active,
.myclass.ng-move.ng-move-active {
  //final animation state
}

.myclass.ng-leave.ng-leave-active {
  //final animation state
}

Documentation can be found here.

Examples

Here's an example of a div that has the ng-if directive. The div will only appear if $scope.bool is true. This div has the class fade so it will fade in and out as the ng-if directive adds and removes the div from the page.

<div ng-if="bool" class="fade">
   Fade me in out
</div>
<button ng-click="bool=true">Fade In!</button>
<button ng-click="bool=false">Fade Out!</button>
/* The starting CSS styles for the enter animation */
.fade.ng-enter {
    transition:0.5s linear all;
      opacity:0;
}

/* The finishing CSS styles for the enter animation */
.fade.ng-enter.ng-enter-active {
    opacity:1;
}

/* now the element will fade out before it is removed from the DOM */
.fade.ng-leave {
    transition:0.5s linear all;
      opacity:1;
}
.fade.ng-leave.ng-leave-active {
    opacity:0;
}

We can also use animation libraries, such as animate.css. Add the CDN link.

<link rel="stylesheet" type="text/css" href="https://cdnjs.cloudflare.com/ajax/libs/animate.css/3.4.0/animate.min.css">

Then add these animations via the animate CSS property. Note that we're using ng-hide and ng-hide-remove for the ng-show directive. These are the animation directives associated with this particular directive.

.container.ng-hide-remove {
  animation: bounceIn 1s;
  opacity: 0;
}

.container.ng-hide {
  animation: bounceOut 1s;
  opacity: 1;
}

.container.ng-hide-remove.ng-hide-remove-active {
  opacity: 1;
}

.container.ng-hide.ng-hide-active {
  opacity: 0;
}

These CSS-Tricks articles are also great resources when playing with transitions and animations.

Note: Animation classes will only be added to items as they are manipulated using supported directives, like ng-repeat, ng-show, ng-hide, ng-if, etc...

But what about JavaScript?

We can define JavaScript animations as well, similar to how we implemented custom filters.

app.animation('.myclass', [function() {
    return {
        enter: function(element, doneFn) {
            // code goes here, then callback
            doneFn();
        },
        leave: function(element, doneFn) {
            // code goes here, then callback
            doneFn();
        }
    }
}]);

This block of code attaches an animation to a class and returns an object with the animations we want to run on enter and leave.

For simplicity, we can use jQuery for animations (this isn't too terrible, since we're strictly using jQuery for its animation capabilities). There's also other alternatives for JavaScript animations, like Velocity.js.

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