EPAM Systems Angular Frontend Developer Interview Questions and Answers

Promises are objects representing the eventual completion or failure of an asynchronous operation. Types refer to the data types in TypeScript.

• Promises are used for handling asynchronous operations in JavaScript.

• They can be in one of three states: pending, fulfilled, or rejected.

• Types in TypeScript help catch errors early by enforcing data types at compile time.

• Examples: Promise.resolve(), Promise.reject(), string, num

Lazy loading is a technique used to load only the necessary resources for a specific part of a web application when it is needed.

• Lazy loading can be achieved in Angular by using the loadChildren property in the route configuration.

• This property allows you to specify a separate module that will be loaded only when the route is activated.

• Lazy loading helps improve the initial loading time of the application by loading mo

Using a shared service or event emitter to facilitate communication between non-relatable components.

• Create a shared service with methods to send and receive data between components

• Use event emitters to emit events and pass data between components

• Utilize RxJS subjects to create an observable data stream for communication

Dependency injection in Angular allows for providing dependencies to a component or service from an external source.

• Dependencies are provided at the module level using providers array in @NgModule decorator.

• Dependencies can also be injected at the component level using constructor parameters.

• Angular's injector resolves dependencies by looking up the provider token in the injector hierarchy.

• Dependency injection helps in...read more

ng-container is a structural directive in Angular used for grouping elements without adding an extra element to the DOM.

• Used to group elements together without adding an extra element to the DOM

• Does not render any extra HTML element

• Helps in organizing code and improving readability

• Useful when applying structural directives like *ngIf or *ngFor

Partial reloading in Angular can be achieved by using the Angular Router to reload only specific parts of the page without refreshing the entire page.

• Use Angular Router to navigate to the same component with different parameters to trigger a partial reload

• Use router events like NavigationStart to detect when a route change is happening and perform partial reloading accordingly

• Use Angular's ChangeDetectionStrategy.OnPus...read more

Angular life cycle refers to the series of events that occur from the creation of a component to its destruction.

• Angular components go through various stages like creation, rendering, updating, and destruction.

• Some key life cycle hooks include ngOnInit, ngOnChanges, ngDoCheck, ngOnDestroy, etc.

• Developers can use these hooks to perform tasks like initializing data, reacting to changes, and cleaning up resources.

RxJS is a library for reactive programming using Observables, allowing for easier handling of asynchronous data streams.

• RxJS stands for Reactive Extensions for JavaScript

• It provides a way to work with asynchronous data streams

• Operators like map, filter, and mergeMap can be used to manipulate and combine streams

• Subscriptions are used to listen for values emitted by Observables