Angular Interview Questions for Developers

Use our engineer-created questions to interview and hire the most qualified Angular developers for your organization.

Angular

The Google-developed Angular consistently ranks as a top front-end framework due to its built-in TypeScript support, two-way data binding, and powerful CLI.

According to the CoderPad 2024 Developer survey, Angular 2+ is the second-most in-demand front-end framework among technical recruiters.

The following sections offer a collection of pragmatic coding tasks and interview inquiries designed to assess a developer’s proficiency in Angular during coding interviews.

Furthermore, a compilation of recommended practices is incorporated to guarantee the accurate measurement of candidates’ Angular expertise through your interview questions.

Table of Contents

Angular example question

Angular directives project

You have two tasks to perform on this simple Angular project:

  • Create a method in src/directives/textchange.directive.ts to add an element to the DOM whose text is a random number.
  • Create a method in src/directives/basiccol.directive.ts to create a box beneath that becomes visible upon generating a random number. There should be a color change when the box is hovered over.

Hint: the Renderer2 class is Angular’s most recommended method for manipulating the DOM. Ensure to use it while creating your functions.

Junior Angular interview questions

Question: The following Angular component is not correctly defining the AppComponent class. Identify and correct the issue.

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

@Component({
  selector: 'app-root',
  template: '<h1>Hello, {{ name }}</h1>',
})
export class AppComponent {
  name: string = 'John Doe';
}

Answer: The issue is that the AppComponent class is missing the closing curly brace (}). To fix it, add the missing curly brace at the end of the class definition as follows:

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

@Component({
  selector: 'app-root',
  template: '<h1>Hello, {{ name }}</h1>',
})
export class AppComponent {
  name: string = 'John Doe';
}

Question: What is dependency injection in Angular and why is it important?

Answer: Dependency injection is a design pattern used in Angular to manage the dependencies of an application. It allows you to provide instances of classes or services to components or other services that need them. By using dependency injection, you can easily replace dependencies, write more modular and testable code, and promote code reusability.

Question: The following Angular template is not correctly binding to the items property of the component. Identify and correct the issue.

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

@Component({
  selector: 'app-item-list',
  template: `
    <ul>
      <li *ngFor="let item of items">{{ item }}</li>
    </ul>
  `,
})
export class ItemListComponent {
  items: string[] = ['Item 1', 'Item 2', 'Item 3'];
}

Answer: The issue is that the items property is not declared as an input property using the @Input decorator. To fix it, modify the component as follows:

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

@Component({
  selector: 'app-item-list',
  template: `
    <ul>
      <li *ngFor="let item of items">{{ item }}</li>
    </ul>
  `,
})
export class ItemListComponent {
  @Input() items: string[] = ['Item 1', 'Item 2', 'Item 3'];
}

Question: Explain the concept of Angular modules and their purpose in an application.

Answer: Angular modules are used to organize and encapsulate related functionality within an Angular application. They serve as containers for components, directives, pipes, and services that belong to a specific feature or functionality. Modules help in organizing the codebase, promoting reusability, and managing dependencies. They also enable lazy loading and improve performance by loading only the required modules on demand.

Intermediate Angular interview questions

Question: The following Angular component is not correctly subscribing to a data service and fetching the data. Identify and correct the issue.

import { Component, OnInit } from '@angular/core';
import { DataService } from './data.service';

@Component({
  selector: 'app-data',
  template: '<ul><li *ngFor="let item of items">{{ item.name }}</li></ul>',
})
export class DataComponent implements OnInit {
  items: any[];

constructor(private dataService: DataService) {}

ngOnInit() {
    this.dataService.getData().subscribe((data: any[]) => {
      this.items = data;
    });
  }
}

Answer: The issue is that the component is not importing the DataService correctly. To fix it, ensure that the correct import statement is added at the top of the file:

import { Component, OnInit } from '@angular/core';
import { DataService } from './data.service';

constructor(private dataService: DataService) {}

ngOnInit() {
    this.dataService.getData().subscribe((data: any[]) => {
      this.items = data;
    });
  }
}

Question: Theoretical: What is the purpose of Angular CLI? How does it simplify Angular development?

Answer: Angular CLI (Command Line Interface) is a command-line tool used for developing Angular applications. It provides a set of powerful features that simplify and automate various development tasks, such as creating new projects, generating components, services, and modules, running tests, optimizing the build, and more. Angular CLI abstracts away the complex configuration and setup required for an Angular project, allowing developers to focus on writing code and improving productivity.

More Angular interview resources

For more guides on improving your knowledge of Angular and acing interviews, we have outlined helpful blog posts below: