Some questions to prepare you for your
Angular Interview
let’s get started
Find more articles
https://medium.com/@drissi.dalanda8
What is the difference between ngIf
and ngFor ?
ngIf: Conditionally includes or excludes an
element based on a boolean expression.
ngFor: Iterates over a list (array) and generates
an element for each item.
dalanda-drissi
What are @Input and @Output
decorators in Angular?
@Input : Allows a parent component to pass data
to a child component..
@Output: Allows a child component to emit
events to a parent component using an
EventEmitter.
dalanda-drissi
What are Angular Services?
Services are singleton classes that provide shared
data, logic, or functions across components,
promoting code reusability and separation of
concerns.
dalanda-drissi
What is Lazy Loading in Angular?
Lazy loading delays the loading of a module until it's
needed, improving application performance by
reducing initial load time.
dalanda-drissi
What are Pipes in Angular?
Pipes transform data for display in templates (e.g.,
formatting dates or numbers). Custom pipes can be
created for custom transformations.
dalanda-drissi
What is Reactive Programming in
Angular with RxJS?
Reactive programming uses Observables to handle
asynchronous operations and events, allowing for
more manageable and declarative code.
dalanda-drissi
What is Angular Router, and how
does it work?
Angular Router enables navigation between different
views or pages of an application. It uses routes defined
in the app-routing.module.ts file, which maps URL
paths to components.
dalanda-drissi
What is the purpose of Angular's
ngOnInit lifecycle hook?
ngOnInit is a lifecycle hook that is called once after the
component's data-bound properties are initialized. It
is commonly used for initializing component data.
dalanda-drissi
How do you pass data between
components in Angular?
Data can be passed between components using
@Input for parent-to-child communication, @Output
with EventEmitter for child-to-parent communication,
and services for sibling or unrelated components.
dalanda-drissi
What is the difference between
ViewChild and ContentChild?
ViewChild queries elements in the component's view,
while ContentChild queries elements projected into
the component via <ng-content>.
dalanda-drissi
What is Angular Universal?
Angular Universal is a technology for server-side
rendering (SSR) that allows Angular applications to be
rendered on the server, improving performance and
SEO.
dalanda-drissi
What is Dependency Injection (DI)
in Angular?
Dependency Injection is a design pattern in Angular
that allows the injection of services or dependencies
into components, making the code modular, reusable,
and easier to test.
dalanda-drissi
How do you handle errors in HTTP
requests in Angular?
Use the .catchError operator in RxJS to handle errors in
HTTP requests made with HttpClient.
dalanda-drissi
What is the difference between
Reactive Forms and TemplateDriven Forms?
Reactive Forms are more flexible and scalable,
created using FormControl and FormGroup in
TypeScript. Template-Driven Forms rely on directives
in the template (ngModel) and are simpler but less
scalable.
dalanda-drissi
How do you optimize an Angular
application for better performance?
Use lazy loading, change detection strategy (OnPush),
optimize template bindings, use trackBy with ngFor,
and minimize bundle sizes with AOT and tree shaking.
dalanda-drissi
What is a Resolver in Angular?
A resolver is a service that fetches data before
navigating to a route, ensuring the required data is
ready when the component loads.
dalanda-drissi
What is the difference between
Observable and Promise in Angular?
Observable is lazy, can handle multiple values over
time, and is cancellable. Promise is eager, handles a
single future value, and is not cancellable.
dalanda-drissi
What are structural directives in
Angular? Name a few.
Structural directives alter the DOM layout by adding or
removing elements. Examples include *ngIf, *ngFor,
and *ngSwitch.
dalanda-drissi
What are Template Reference
Variables in Angular?
Template Reference Variables, declared with #, are
used to access DOM elements and component
instances directly in the template.
dalanda-drissi
What are Angular Guards, and what
are they used for?
Angular Guards (CanActivate, CanDeactivate, etc.)
control navigation and access to routes based on
specific conditions, enhancing security and user
experience.
dalanda-drissi
What is the purpose of NgZone in
Angular?
NgZone enables Angular to run change detection
outside of the Angular zone, optimizing performance
by limiting unnecessary checks.
dalanda-drissi
What is trackBy in ngFor, and why is it
used?
trackBy optimizes rendering in ngFor by tracking items
with a unique identifier, preventing re-rendering of
unchanged items and improving performance.
dalanda-drissi
What is the difference between
@Injectable and @Component?
@Injectable marks a class as available for
dependency injection, while @Component marks a
class as an Angular component and associates it with
a template.
dalanda-drissi
What are HttpInterceptors in Angular?
HttpInterceptors are part of Angular's HttpClient
module that allow developers to modify outgoing HTTP
requests or incoming responses, typically used for
adding headers or handling errors.
dalanda-drissi
What is ngModel and how does it work
in Angular?
ngModel is a directive used for two-way data binding
in template-driven forms. It binds input, select,
textarea, etc., to a property in the component's class.
dalanda-drissi
What is an Injector in Angular?
An Injector is a service locator that provides instances
of services or dependencies. It is part of Angular's
dependency injection system, creating and managing
dependencies
dalanda-drissi