How do you create reusable Animations in Angular 2

Question

One possible way is to put animation trigger code in separate file and export it as const variable and use it in component as below.

animations.ts

import { trigger, state, style, transition, animate } from '@angular/core';

export const slideIn = trigger('slideIn', [
  state('*', style({
    transform: 'translateX(100%)',
  })),
  state('in', style({
    transform: 'translateX(0)',
  })),
  state('out',   style({
    transform: 'translateX(-100%)',
  })),
  transition('* => in', animate('600ms ease-in')),
  transition('in => out', animate('600ms ease-in'))
]);

album-display.component.ts

import { slideIn } from './animations'; // path to your animations.ts file

@Component({
    //moduleId: module.id,
    selector: 'album-display',
    templateUrl: './albumDisplay.html',
    animations: [
      slideIn
    ]
})
export class AlbumDisplay implements OnInit {
    slideInState = 'in';
    ...
}

Maybe it's a bit late, but I'd still like to put an answer for a more dynamic version of the trigger.

Put animation trigger code in separate file and export it as function.

translate.ts

import { AnimationEntryMetadata, trigger, state, style, transition, animate } from '@angular/core';

export function TranslateX( name: string, x: string, duration: number ): AnimationEntryMetadata {
    return trigger( name, [
            state('false', style({ transform: 'translateX(0)' }) ),
            state('true',  style({ transform: 'translateX(' + x + ')' }) ),
            transition('0 => 1', animate( duration + 'ms ease-in')),
            transition('1 => 0', animate( duration + 'ms ease-out')),
        ]);
}

so, in the Component app.component.ts

import { TranslateX } from './translate';

@Component({
    ...
    templateUrl: './app.component.html',
    animations:   [ 
                    TranslateX( 'trigger1Title','-100%', 200 ),
                    TranslateX( 'trigger2Title','20vw', 700 )
                  ]
    ...
})

and in template app.component.html

...
<div [@trigger1Title]="token1"> ... </div>
<div [@trigger2Title]="token2"> ... </div>
...

You can customize the trigger with more input data, for example separating the transition times, and so on.

Router Animation Example in Angular 4

I just finished tackling router animations myself using Angular 4, here's a couple of example animations I came up with for a fade in transition and slide in/out transition.

Check out this post for more details and a live demo.

Angular 4 Slide in/out animation

// import the required animation functions from the angular animations module
import { trigger, state, animate, transition, style } from '@angular/animations';
 
export const slideInOutAnimation =
    // trigger name for attaching this animation to an element using the [@triggerName] syntax
    trigger('slideInOutAnimation', [
 
        // end state styles for route container (host)
        state('*', style({
            // the view covers the whole screen with a semi tranparent background
            position: 'fixed',
            top: 0,
            left: 0,
            right: 0,
            bottom: 0,
            backgroundColor: 'rgba(0, 0, 0, 0.8)'
        })),
 
        // route 'enter' transition
        transition(':enter', [
 
            // styles at start of transition
            style({
                // start with the content positioned off the right of the screen,
                // -400% is required instead of -100% because the negative position adds to the width of the element
                right: '-400%',
 
                // start with background opacity set to 0 (invisible)
                backgroundColor: 'rgba(0, 0, 0, 0)'
            }),
 
            // animation and styles at end of transition
            animate('.5s ease-in-out', style({
                // transition the right position to 0 which slides the content into view
                right: 0,
 
                // transition the background opacity to 0.8 to fade it in
                backgroundColor: 'rgba(0, 0, 0, 0.8)'
            }))
        ]),
 
        // route 'leave' transition
        transition(':leave', [
            // animation and styles at end of transition
            animate('.5s ease-in-out', style({
                // transition the right position to -400% which slides the content out of view
                right: '-400%',
 
                // transition the background opacity to 0 to fade it out
                backgroundColor: 'rgba(0, 0, 0, 0)'
            }))
        ])
    ]);

Angular 4 Fade in animation

// import the required animation functions from the angular animations module
import { trigger, state, animate, transition, style } from '@angular/animations';
 
export const fadeInAnimation =
    // trigger name for attaching this animation to an element using the [@triggerName] syntax
    trigger('fadeInAnimation', [
 
        // route 'enter' transition
        transition(':enter', [
 
            // css styles at start of transition
            style({ opacity: 0 }),
 
            // animation and styles at end of transition
            animate('.3s', style({ opacity: 1 }))
        ]),
    ]);

Component with transition attached

import { Component } from '@angular/core';
 
// import fade in animation
import { fadeInAnimation } from '../_animations/index';
 
@Component({
    moduleId: module.id.toString(),
    templateUrl: 'home.component.html',
 
    // make fade in animation available to this component
    animations: [fadeInAnimation],
 
    // attach the fade in animation to the host (root) element of this component
    host: { '[@fadeInAnimation]': '' }
})
 
export class HomeComponent {
}

Proper solution would be to have animations supported in Directives.

It is not the case, but there is a issue for that on Angular's Github: https://github.com/angular/angular/issues/9947

Hope it will be solved soon.