How to Implement Animations with Angular 2 Directives

Question

How to Implement Animations with Angular 2 Directives

Incorporating a special Directive onto elements to monitor their current scroll position seems like a handy feature.

Here's an example:

@Directive({
    selector: '[my-scroll-animation]'
})

My goal is to make the element appear on screen with an animation once it reaches a specific position. In a Component, I could easily achieve this by using an animations property in the host settings to trigger the animation.

Here's an idea of what I have in mind:

import { myScrollAnimation } from './animations';

@Directive({
    selector: '[my-scroll-animation]'
    animations: [myScrollAnimation] // <- is this feasible?
})

Any suggestions on implementing this animation functionality within a Directive?

Framework in Use: Angular 4.0.0-rc.4

javascript typescript angular

Answer 1

Answer №1

Angular 4.2 introduced significant animation enhancements, one of which is the AnimationBuilder, enabling the creation of animations programmatically.

To utilize this feature, simply inject AnimationBuilder into your directive, allowing you to transform any AnimationMetadata into a functional animation.

@Directive({
  selector: '[zetFadeInOut]',
})
export class FadeInOutDirective {

  @Input()
  set show(show: boolean) {
    const metadata = show ? this.fadeIn() : this.fadeOut();

    const factory = this.builder.build(metadata);
    const player = factory.create(this.el.nativeElement);

    player.play();
  }

  constructor(private builder: AnimationBuilder, private el: ElementRef) {}

  private fadeIn(): AnimationMetadata[] {
    return [
      style({ opacity: 0 }),
      animate('400ms ease-in', style({ opacity: 1 })),
    ];
  }

  private fadeOut(): AnimationMetadata[] {
    return [
      style({ opacity: '*' }),
      animate('400ms ease-in', style({ opacity: 0 })),
    ];
  }
}

Example repository
Exploring the Latest Animation Features in Angular 4.2+

Answer 2

Angular 4.2 introduced significant animation enhancements, one of which is the AnimationBuilder, enabling the creation of animations programmatically.

To utilize this feature, simply inject AnimationBuilder into your directive, allowing you to transform any AnimationMetadata into a functional animation.

@Directive({
  selector: '[zetFadeInOut]',
})
export class FadeInOutDirective {

  @Input()
  set show(show: boolean) {
    const metadata = show ? this.fadeIn() : this.fadeOut();

    const factory = this.builder.build(metadata);
    const player = factory.create(this.el.nativeElement);

    player.play();
  }

  constructor(private builder: AnimationBuilder, private el: ElementRef) {}

  private fadeIn(): AnimationMetadata[] {
    return [
      style({ opacity: 0 }),
      animate('400ms ease-in', style({ opacity: 1 })),
    ];
  }

  private fadeOut(): AnimationMetadata[] {
    return [
      style({ opacity: '*' }),
      animate('400ms ease-in', style({ opacity: 0 })),
    ];
  }
}

Example repository
Exploring the Latest Animation Features in Angular 4.2+

Answer 3

Answer №2

After coming across a helpful workaround from this response, I decided to implement a solution inspired by benshabatnoam's answer.

It turns out that directives are essentially components without templates. By utilizing an attribute selector (e.g. [selector]) and setting the template as

<ng-content></ng-content>

, you can mimic the behavior of a directive using a component.

So, I created a 'foux-directive' component in this way:

@Component({
    selector: '[fadeInAnimation]',
    animations: [
        trigger('fadeIn', [
             transition(':enter', [
                 style({opacity:'0'}),
                 animate(200, style({opacity:'1'}))
             ])
        ])
    ], 
    template: `<ng-content></ng-content>`,
})
export class FadeInDirective {
    @HostBinding('@fadeIn') trigger = '';
}

You can then use this component just like any other directive:

<div fadeInAnimation> something I want to animate </div>

Answer 4

After coming across a helpful workaround from this response, I decided to implement a solution inspired by benshabatnoam's answer.

It turns out that directives are essentially components without templates. By utilizing an attribute selector (e.g. [selector]) and setting the template as

<ng-content></ng-content>

, you can mimic the behavior of a directive using a component.

So, I created a 'foux-directive' component in this way:

@Component({
    selector: '[fadeInAnimation]',
    animations: [
        trigger('fadeIn', [
             transition(':enter', [
                 style({opacity:'0'}),
                 animate(200, style({opacity:'1'}))
             ])
        ])
    ], 
    template: `<ng-content></ng-content>`,
})
export class FadeInDirective {
    @HostBinding('@fadeIn') trigger = '';
}

You can then use this component just like any other directive:

<div fadeInAnimation> something I want to animate </div>

Answer 5

Answer №3

Like I mentioned in response to your question earlier.

You have the option to set up the animation configuration in the parent component. Then, the directive will simply apply a class to its host element when the specified condition is met.

Within your directive, you could include something along the lines of:

@Input() animationTriggerClass = "animate-me";
@HostBinding('[@animationName]') animationTrigger = ""; 

// when the condition is met
this.animationTrigger = this.animationTriggerClass;

Answer 6

Like I mentioned in response to your question earlier.

You have the option to set up the animation configuration in the parent component. Then, the directive will simply apply a class to its host element when the specified condition is met.

Within your directive, you could include something along the lines of:

@Input() animationTriggerClass = "animate-me";
@HostBinding('[@animationName]') animationTrigger = ""; 

// when the condition is met
this.animationTrigger = this.animationTriggerClass;

Answer 7

Answer №4

Let's dive in. Perfect for small animations.

This code utilizes AnimationPlayer + AnimationBuilder directly, eliminating the need to toggle a state back and forth to trigger the animation. It was inspired by and further simplified from this code snippet.

import { Directive, Input, HostListener } from '@angular/core';
import { ElementRef } from '@angular/core';
import {
    AnimationPlayer,
    AnimationBuilder
} from '@angular/animations';

@Directive({
    selector: '[clickAnimation]',
})
export class ClickAnimationDirective {
    private player: AnimationPlayer;

    @Input() clickAnimation: any;

    @HostListener('click', ['$event'])
    onClick() {
        // clean up just in case
        if (this.player) { this.player.destroy(); }

        const factory = this.builder.build(this.clickAnimation);
        const player = factory.create(this.el.nativeElement);

        // ensure resetting to original state
        player.onDone(() => { player.reset(); });
        player.play();
    }

    constructor(private builder: AnimationBuilder, private el: ElementRef) { }
}

In your HTML template:

<app-button
    [clickAnimation]="trafficLight"
    ...

In your component class:

public trafficLight: AnimationMetadata[] = [
    style({ borderColor: 'red' }),
    animate('400ms ease-in', style({ borderColor: 'yellow' })),
    animate('400ms ease-in', style({ borderColor: 'cyan' })),
    //alternative way to ensure back to original
    // animate('400ms ease-in', style({ borderColor: '*' })), 
];

Answer 8

Let's dive in. Perfect for small animations.

This code utilizes AnimationPlayer + AnimationBuilder directly, eliminating the need to toggle a state back and forth to trigger the animation. It was inspired by and further simplified from this code snippet.

import { Directive, Input, HostListener } from '@angular/core';
import { ElementRef } from '@angular/core';
import {
    AnimationPlayer,
    AnimationBuilder
} from '@angular/animations';

@Directive({
    selector: '[clickAnimation]',
})
export class ClickAnimationDirective {
    private player: AnimationPlayer;

    @Input() clickAnimation: any;

    @HostListener('click', ['$event'])
    onClick() {
        // clean up just in case
        if (this.player) { this.player.destroy(); }

        const factory = this.builder.build(this.clickAnimation);
        const player = factory.create(this.el.nativeElement);

        // ensure resetting to original state
        player.onDone(() => { player.reset(); });
        player.play();
    }

    constructor(private builder: AnimationBuilder, private el: ElementRef) { }
}

In your HTML template:

<app-button
    [clickAnimation]="trafficLight"
    ...

In your component class:

public trafficLight: AnimationMetadata[] = [
    style({ borderColor: 'red' }),
    animate('400ms ease-in', style({ borderColor: 'yellow' })),
    animate('400ms ease-in', style({ borderColor: 'cyan' })),
    //alternative way to ensure back to original
    // animate('400ms ease-in', style({ borderColor: '*' })), 
];

Answer 9

Answer №5

An issue has been reported in the Angular's git repository, dated 28/08/17. To escalate the resolution process, kindly show your support by upvoting this problem.

Answer 10

An issue has been reported in the Angular's git repository, dated 28/08/17. To escalate the resolution process, kindly show your support by upvoting this problem.

Answer 11

Answer №6

Although my response may be a bit tardy, I successfully incorporated animations by utilizing the ElementRef to target the element to which the directive is applied, and subsequently utilizing the built-in native element's animate function:

@Directive({
  selector: '[grayscaleFade]'
})
export class GrayscaleFadeDirective {

  constructor(private rawElement: ElementRef) {
    this.rawElement.nativeElement.style.filter = "grayscale(1)"
  }

  @HostListener('mouseenter') onMouseEnter() {
    this.rawElement.nativeElement.animate([
        {filter: "grayscale(1)"},
        {filter: "grayscale(0)"},
      ],
      {
        duration: 300,
        delay: 0,
        fill: "both",
        easing :'ease-in-out',
        trigger: 'enter'
      }).play();
  }

  @HostListener('mouseleave') onMouseExit() {
    this.rawElement.nativeElement.animate([
        {filter: "grayscale(0)"},
        {filter: "grayscale(1)"},
      ],
      {
        duration: 300,
        delay: 0,
        fill: "both",
        easing :'ease-in-out',
        trigger: 'enter'
      }).play();
  }
}

It's worth noting that without calling .play(), this won't execute. It took me some time to discover that.

It appears that animate isn't an Angular function but rather a part of the MDN specifications: https://developer.mozilla.org/en-US/docs/Web/API/Element/animate

Answer 12

Although my response may be a bit tardy, I successfully incorporated animations by utilizing the ElementRef to target the element to which the directive is applied, and subsequently utilizing the built-in native element's animate function:

@Directive({
  selector: '[grayscaleFade]'
})
export class GrayscaleFadeDirective {

  constructor(private rawElement: ElementRef) {
    this.rawElement.nativeElement.style.filter = "grayscale(1)"
  }

  @HostListener('mouseenter') onMouseEnter() {
    this.rawElement.nativeElement.animate([
        {filter: "grayscale(1)"},
        {filter: "grayscale(0)"},
      ],
      {
        duration: 300,
        delay: 0,
        fill: "both",
        easing :'ease-in-out',
        trigger: 'enter'
      }).play();
  }

  @HostListener('mouseleave') onMouseExit() {
    this.rawElement.nativeElement.animate([
        {filter: "grayscale(0)"},
        {filter: "grayscale(1)"},
      ],
      {
        duration: 300,
        delay: 0,
        fill: "both",
        easing :'ease-in-out',
        trigger: 'enter'
      }).play();
  }
}

It's worth noting that without calling .play(), this won't execute. It took me some time to discover that.

It appears that animate isn't an Angular function but rather a part of the MDN specifications: https://developer.mozilla.org/en-US/docs/Web/API/Element/animate

How to Implement Animations with Angular 2 Directives

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

Answer №6

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