HCL Group User Interface and Angular Developer Interview Questions and Answers

Dependency Injection is a design pattern used in Angular to inject dependencies into a component or service.

• It allows for easier testing and maintenance of code

• Dependencies are injected through the constructor of a component or service

• Angular has its own Dependency Injection system built-in

• Services can be shared across multiple components through Dependency Injection

Observables are streams of data that can be subscribed to, while promises are a one-time operation that returns a single value.

• Observables can emit multiple values over time, while promises only return a single value.

• Observables can be cancelled, while promises cannot.

• Observables are lazy, meaning they only execute when subscribed to, while promises execute immediately.

• Observables have operators that can transform, fil...read more

Directives are markers on a DOM element that tell AngularJS to attach a specified behavior to that DOM element.

• Directives are used to create reusable components.

• They can be used to manipulate the DOM.

• They can be used to add behavior to an existing DOM element.

• They can be used to create custom attributes.

• Examples include ng-repeat, ng-model, and ng-show.

Pure pipes are stateless and only depend on input data, while impure pipes have internal state and can have side effects.

• Pure pipes are faster and more efficient than impure pipes.

• Pure pipes are used for simple transformations of data, while impure pipes are used for more complex transformations.

• Examples of pure pipes include currency and date formatting, while examples of impure pipes include filtering and sorting.

• To ...read more

Interceptors are used to intercept HTTP requests and responses to perform transformations or error handling.

• Interceptors can be used to add headers to outgoing requests or handle errors in incoming responses.

• They can also be used to modify the request or response before it is sent or received.

• Interceptors can be global or specific to a certain request or response.

• They are useful for implementing authentication, caching...read more