style

Experimental Function

Class Export

export style(tokens: string | {[key: string]: string | number} |
    Array<string|{[key: string]: string | number}>) : AnimationStyleMetadata

style is an animation-specific function that is designed to be used inside of Angular2's animation DSL language. If this information is new, please navigate to the component animations metadata page to gain a better understanding of how animations in Angular2 are used.

style declares a key/value object containing CSS properties/styles that can then be used for animation states, within an animation sequence, or as styling data for both animate and keyframes.

Usage

style takes in a key/value string map as data and expects one or more CSS property/value pairs to be defined.

// string values are used for css properties
style({ background: "red", color: "blue" })

// numerical (pixel) values are also supported
style({ width: 100, height: 0 })

Auto-styles (using *)

When an asterix (*) character is used as a value then it will be detected from the element being animated and applied as animation data when the animation starts.

This feature proves useful for a state depending on layout and/or environment factors; in such cases the styles are calculated just before the animation starts.

// the steps below will animate from 0 to the
// actual height of the element
style({ height: 0 }),
animate("1s", style({ height: "*" }))

Example (live demo)

import {Component, NgModule, animate, state, style, transition, trigger} from '@angular/core';
import {BrowserModule} from '@angular/platform-browser';

@Component({
  selector: 'example-app',
  styles: [`
    .toggle-container {
      background-color:white;
      border:10px solid black;
      width:200px;
      text-align:center;
      line-height:100px;
      font-size:50px;
      box-sizing:border-box;
      overflow:hidden;
    }
  `],
  animations: [trigger(
      'openClose',
      [
        state('collapsed, void', style({height: '0px', color: 'maroon', borderColor: 'maroon'})),
        state('expanded', style({height: '*', borderColor: 'green', color: 'green'})),
        transition(
            'collapsed <=> expanded', [animate(500, style({height: '250px'})), animate(500)])
      ])],
  template: `
    <button (click)="expand()">Open</button>
    <button (click)="collapse()">Closed</button>
    <hr />
    <div class="toggle-container" [@openClose]="stateExpression">
      Look at this box
    </div>
  `
})
export class MyExpandoCmp {
  stateExpression: string;
  constructor() { this.collapse(); }
  expand() { this.stateExpression = 'expanded'; }
  collapse() { this.stateExpression = 'collapsed'; }
}

@NgModule({imports: [BrowserModule], declarations: [MyExpandoCmp], bootstrap: [MyExpandoCmp]})
export class AppModule {
}

exported from @angular/core/index defined in @angular/core/src/animation/metadata.ts