Promien Consultancy Services Interview Questions and Answers

Using services or @Input/@Output decorators to share data between components

• Use services to create a shared data service that can be injected into multiple components

• Use @Input decorator to pass data from parent to child component

• Use @Output decorator with EventEmitter to emit events and pass data from child to parent component

Pipe is a feature in Angular that allows transforming data before displaying it in the view.

• Pipes are used to format and filter data in Angular templates.

• They can be used to transform data types, apply currency and date formatting, and filter data based on certain criteria.

• Pipes can be chained together to perform multiple transformations on the same data.

• Custom pipes can also be created to perform specific transformations not provided by the built-in pipes.

Implementing a login page involves creating a form for users to input their credentials and validating them against a database.

• Create a login form with fields for username and password

• Use Angular's form validation to ensure required fields are filled out

• Send the user's credentials to a backend server for authentication

• Upon successful authentication, redirect the user to the main application page

Promises are used for asynchronous operations that return a single value, while Observables are used for streams of data.

• Promises return a single value, while Observables can return multiple values over time.

• Observables can be cancelled, while Promises cannot.

• Observables have operators like map, filter, and reduce, while Promises do not.

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

• Promises are easier to understand and ...read more

Components can communicate using @Input and @Output decorators, services, and event emitters.

• Use @Input decorator to pass data from parent to child component

• Use @Output decorator and EventEmitter to emit events from child to parent component

• Use services to share data between components