How Angular differs from React and Vue - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a standalone Angular component.

Angular

import { Component } from '@angular/core';

@Component({
  selector: 'app-hello',
  template: `<h1>Hello Angular!</h1>`,
  standalone: [1]
})
export class HelloComponent {}

Drag options to blanks, or click blank then click option'

Atrue

Bundefined

Cnull

Dfalse

Attempts:

3 left

💡 Hint

Common Mistakes

Setting standalone to false or omitting it causes the component to require NgModules.

Angular standalone components require standalone: true to work without NgModules.

2fill in blank

medium

Complete the code to update a signal in Angular 17+.

Angular

import { Component, signal, inject } from '@angular/core';

@Component({
  standalone: true,
  selector: 'app-counter',
  template: `<button (click)="increment()">Count: {{ count() }}</button>`
})
export class CounterComponent {
  count = signal(0);
  increment() {
    [1].set([1]() + 1);
  }
}

Drag options to blanks, or click blank then click option'

Athis.count

Bcount

Cthis.count()

Dcount()

Attempts:

3 left

💡 Hint

Common Mistakes

Using the signal variable directly without calling it as a function.

To update a signal, call it as a function to get its current value, then set the new value.

3fill in blank

hard

Fix the error in the Angular template syntax.

Angular

<button (click)="[1]()">Click me</button>

Drag options to blanks, or click blank then click option'

A"increment"

Bincrement

Cincrement()

D(increment)

Attempts:

3 left

💡 Hint

Common Mistakes

Using double curly braces inside event bindings causes errors.

In Angular templates, event bindings use the function name with parentheses inside the quotes.

4fill in blank

hard

Fill both blanks to use Angular's new control flow directives for a list.

Angular

<ul>
  @if ([1]) {
    @for (let item of items; track item) {
      <li>{{ item }}</li>
    }
  } @else if ([2]) {
    <p>No items</p>
  }
</ul>

Drag options to blanks, or click blank then click option'

Aitems.length > 0

Bitems.length === 0

Citems

Ditem

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong variable or condition in the @if directive.

Use @if with a condition to show the list only if it has items, and else for the empty case.

5fill in blank

hard

Fill all three blanks to create a reactive form control with Angular signals.

Angular

import { Component, signal } from '@angular/core';

@Component({
  standalone: true,
  selector: 'app-input',
  template: `<input [value]="[1]" (input)="[2].set($event.target.value)" />`
})
export class InputComponent {
  [3] = signal('');
}

Drag options to blanks, or click blank then click option'

AinputValue()

BinputValue

Attempts:

3 left

💡 Hint

Common Mistakes

Not calling the signal as a function to get its value.

The input's value is read by calling the signal as a function. The signal variable is updated on input events.

Practice

1. Which statement best describes Angular compared to React and Vue?

easy

A. Angular is a full framework with built-in features and uses TypeScript.

B. Angular is a lightweight UI library focusing only on the view layer.

C. Angular uses JSX syntax for templating like React.

D. Angular is a progressive framework with simple single-file components.

Solution

1. Step 1: Understand Angular's scope

   Angular is a complete framework that includes routing, forms, HTTP, and more, unlike React which is mainly a UI library.

2. Step 2: Compare Angular's language and syntax

   Angular uses TypeScript and decorators, while React uses JavaScript and JSX, and Vue uses simpler syntax with single-file components.

3. Final Answer:

   Angular is a full framework with built-in features and uses TypeScript. -> Option A

4. Quick Check:

   Angular = full framework + TypeScript [OK]

Hint: Angular = full framework + TypeScript, React = UI library [OK]

Common Mistakes:

• Confusing Angular as just a UI library like React
• Thinking Angular uses JSX syntax
• Assuming Angular uses single-file components like Vue

2. Which syntax is correct for defining a component in Angular?

easy

A. const AppComponent = { template: 'Hello' }

B. function AppComponent() { return <div>Hello</div>; }

C. @Component({ selector: 'app-root', templateUrl: './app.component.html' }) export class AppComponent { }

D. Vue.component('app-root', { template: 'Hello' })

Solution

1. Step 1: Identify Angular component syntax

   Angular components use the @Component decorator with metadata and a TypeScript class.

2. Step 2: Compare with other frameworks

   React uses functions returning JSX, Vue uses objects or Vue.component, so options A, B, D are not Angular syntax.

3. Final Answer:

   @Component({ selector: 'app-root', templateUrl: './app.component.html' }) export class AppComponent { } -> Option C

4. Quick Check:

   Angular uses @Component decorator [OK]

Hint: Angular components use @Component decorator and class [OK]

Common Mistakes:

• Using React function syntax for Angular components
• Using Vue component registration syntax in Angular
• Omitting the @Component decorator in Angular

3. Given this Angular code snippet, what will be the rendered output?

@Component({ selector: 'app-msg', template: `
{{ message }}
` }) export class MsgComponent { message = 'Hello Angular'; }

medium

A. Hello Angular

B. {{ message }}

C. Error: message is undefined

D. Hello React

Solution

1. Step 1: Understand Angular interpolation

   The template uses {{ message }} which Angular replaces with the component's message property value.

2. Step 2: Check the message property value

   The message property is set to 'Hello Angular', so the rendered output is a paragraph with that text.

3. Final Answer:

   <p>Hello Angular</p> -> Option A

4. Quick Check:

   Angular interpolation outputs property value [OK]

Hint: {{ }} shows component property value in Angular templates [OK]

Common Mistakes:

• Thinking {{ message }} prints literally
• Assuming message is undefined without initialization
• Confusing Angular interpolation with React JSX

4. Identify the error in this Angular component code:

@Component({ selector: 'app-test', template: `
{{ title }}
` }) export class TestComponent { title: string; }

medium

A. Incorrect selector name format

B. Missing initialization of the 'title' property

C. Template syntax should use square brackets instead of curly braces

D. Class should not be exported

Solution

1. Step 1: Check property declaration

   The title property is declared but not initialized, so it is undefined at runtime.

2. Step 2: Understand Angular template binding

   Angular tries to display {{ title }}, but since title is undefined, it will render empty or cause issues.

3. Final Answer:

   Missing initialization of the 'title' property -> Option B

4. Quick Check:

   Uninitialized property causes undefined display [OK]

Hint: Always initialize component properties before use [OK]

Common Mistakes:

• Thinking selector format is wrong
• Confusing Angular interpolation syntax
• Believing export keyword is disallowed

5. Which feature uniquely distinguishes Angular from React and Vue in large-scale app development?

hard

A. Lightweight virtual DOM for fast rendering

B. Use of JSX syntax for templating UI components

C. Progressive adoption with optional core features

D. Built-in dependency injection system for managing services

Solution

1. Step 1: Identify Angular's unique architecture feature

   Angular includes a built-in dependency injection system to manage services and components efficiently.

2. Step 2: Compare with React and Vue features

   React uses JSX and does not have built-in dependency injection; Vue is progressive and lightweight but lacks Angular's DI system.

3. Final Answer:

   Built-in dependency injection system for managing services -> Option D

4. Quick Check:

   Angular's DI system is unique among these frameworks [OK]

Hint: Angular has built-in dependency injection, React and Vue do not [OK]

Common Mistakes:

• Confusing JSX as Angular feature
• Thinking Vue has built-in DI like Angular
• Assuming virtual DOM is unique to Angular