Route transition animations in Angular - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

Understanding basic route transition animation triggers

Given the Angular animation trigger below, what will happen when the route changes from 'home' to 'about'?

Angular

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

export const slideInAnimation = trigger('routeAnimations', [
  transition('home => about', [
    style({ transform: 'translateX(100%)' }),
    animate('300ms ease-in', style({ transform: 'translateX(0%)' }))
  ])
]);

A No animation occurs because the trigger is incorrect.

B The old route slides out to the left over 300ms.

C The new route fades in with no sliding effect.

D The new route slides in from the right over 300ms.

💡 Hint

Look at the initial style and the animate style in the transition.

The transition defines that when moving from 'home' to 'about', the new route starts off-screen to the right (translateX(100%)) and animates to its normal position (translateX(0%)) over 300ms. This causes a sliding in effect from the right.

📝 Syntax

intermediate

Identify the syntax error in this route animation definition

Which option contains the correct syntax for defining a route transition animation in Angular?

Angular

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

export const fadeAnimation = trigger('fadeAnimation', [
  transition(':enter', [
    style({ opacity: 0 }),
    animate('500ms', style({ opacity: 1 }))
  ])
]);

A transition(':enter', [style({opacity: 0}), animate('500ms', style({opacity: 1}))])

B transition('enter', [style({opacity: 0}), animate('500ms', style({opacity: 1}))])

C transition(':enter', style({opacity: 0}), animate('500ms', style({opacity: 1})))

D transition(':enter', [style({opacity: 0}), animate('500ms', {opacity: 1})])

💡 Hint

Check the use of brackets and the special ':enter' state syntax.

Option A correctly uses the ':enter' state with an array of animation steps. Option A misses the colon in ':enter'. Option A misses the array brackets around the animation steps. Option A incorrectly passes an object instead of a style() call to animate.

❓ state_output

advanced

What is the final opacity after this route transition animation?

Consider this Angular animation for route transitions. What will be the opacity of the component after the animation completes when transitioning from 'login' to 'dashboard'?

Angular

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

export const fadeRouteAnimation = trigger('fadeRoute', [
  transition('login => dashboard', [
    style({ opacity: 0 }),
    animate('400ms ease-out', style({ opacity: 1 }))
  ])
]);

A 1 (fully opaque)

B 0 (fully transparent)

C 0.5 (semi-transparent)

D Animation does not change opacity

💡 Hint

Look at the final style in the animate() call.

The animation starts with opacity 0 and animates to opacity 1 over 400ms. After the animation finishes, the component is fully opaque (opacity 1).

🔧 Debug

advanced

Why does this route animation not trigger on navigation?

Given this Angular route animation code, why does the animation not run when navigating between routes?

Angular

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

export const slideAnimation = trigger('slideAnimation', [
  transition('* => *', [
    style({ transform: 'translateX(-100%)' }),
    animate('300ms ease-in', style({ transform: 'translateX(0%)' }))
  ])
]);

// In component template:
// <div [@slideAnimation]="getRouteAnimationData()">...</div>

// getRouteAnimationData() returns the current route's 'animation' data property.

A The animation trigger name does not match the template binding.

B The transition '* => *' is invalid syntax and prevents animation.

C The getRouteAnimationData() method returns undefined, so no animation state changes.

D The component is missing the BrowserAnimationsModule import in the app module.

💡 Hint

Check what the animation trigger depends on to detect changes.

The animation trigger depends on the value returned by getRouteAnimationData(). If this method returns undefined or the same value on every call, Angular does not detect a state change and the animation does not run.

🧠 Conceptual

expert

How does Angular determine when to run route transition animations?

In Angular, what mechanism triggers route transition animations to run when navigating between routes?

A Animations run only if the route component implements a special animation interface.

B Angular compares the 'animation' data property of the activated routes and triggers animations when they differ.

C Animations run automatically on every route change without any configuration.

D Angular triggers animations based on URL string comparison only.

💡 Hint

Think about how Angular uses route data to control animations.

Angular uses the 'animation' data property defined in route configurations to detect changes between routes. When this property differs between the current and next route, Angular triggers the defined route transition animations.