Deloitte Angular Interview Questions for 3-4+ years
Shared question set for 3-4+ years of experience, L1 round. Topics and wording follow the supplied notes; these are questions, not official company guidance.
- Why were arrow functions introduced when traditional functions already existed?
- Explain how the JavaScript event loop works.
- What are callback functions?
- Explain hoisting in JavaScript.
- What is the difference between var, let, and const?
- What is the difference between map(), filter(), reduce(), and forEach()?
- What is localStorage? How is it different from sessionStorage?
- Explain prototype in JavaScript.
- What is the difference between relative, absolute, fixed, and sticky positioning?
- What are semantic and non-semantic HTML elements?
- Explain Angular component lifecycle hooks. In which lifecycle hook should you call an API, and why?
- What is Angular change detection?
- How can you share data between Angular components?
- Explain Angular routing. How do you navigate with route parameters and read query parameters?
- Explain interface, class, and type in TypeScript. Which do you prefer and when would you use extends?
- Have you used Angular Signals? How do you change the value of a Signal?
- What are the different types of Signals?
- How do you add validation to a Reactive Form?
- What are pipes used for?
- Have you created any custom pipes?
- What is @HostListener?
- Where do you write API call methods in an Angular application?
- Where should utility functions be kept?
- Suppose some pages of your website should only be accessible to logged-in users. How would you implement this?
- Are you writing test cases? Why should we write test cases?
- Do you know how an Angular application is deployed to a server? How many environments does your application have?
- Given an array of products, filter with different conditions and explain the array methods find, filter, includes and map.
- Flatten a nested array using a recursive function.