Introduction

Question 1

What is Angular?

Answer 1

Angular is a TypeScript-based open-source web application framework developed by the Angular Team at Google

Question 2

What is TypeScript?

Answer 2

It is an open-source programming language on top of JavaScript to support static typing and other functionalities.

Question 3

What is JavaScript?

Answer 3

– High-level, multi-paradigm (OO, functional) programming language

– Alongside HTML and CSS, JavaScript is one of the core technologies of the Web

– Initially only implemented client-side in web browsers, but JavaScript is now available server-side, in mobile and desktop apps too

• Dynamically and weakly typed

Question 4

What are the main building blocks of an Angular application?

Answer 4

Modules, Components and Services

Question 5

What are some of the technologies you might include in your environment to create an Angular application?

Answer 5

NodeJS
npm
Angular CLI

Question 6

What is the Angular CLI?

Answer 6

It is a Command-line interface tool that you use to develop Angular applications

Question 7

What is Node.js?

Answer 7

• Node.js is an open-source JavaScript runtime environment that executes JavaScript code outside of a browser (It allows for servers to be written using JavaScript)

Question 8

What is npm?

Answer 8

– Node Package Manager – package (dependency) manager for Node.js packages

Question 9

What is AJAX?

Answer 9

• Asynchronous JavaScript and XML
• Allows web pages to be updated asynchronously by exchanging data with a web server
• Transports data in XML, plain text, or JSON format (JSON is the most widespread nowadays)

Question 10

What are directives in Angular?

Answer 10

• Directives are basically function calls in the HTML template
• There are three types: Component, Structural and Attribute

Question 11

What is the use of @Input and @Output?

Answer 11

• They are used for communication between Angular Components, which are in Parent-Child Relationship
• Both of them are used in the Child Component
• We use @Input when we are passing data from the parent to the child component and @Output when we emit an event from the Child that the parent can subscribe to

Question 12

What is Dependency Injection in Angular?

Answer 12

When a component is dependent on another component the dependency is injected/provided during runtime by Angular’s built-in dependency injection system

Question 13

In what ways can a component (.ts) and a template (.html) file communicate with each other?

Answer 13

• interpolation: {{}}
• property binding: []
• event binding: ()
• two-way binding: [()]

Question 14

What are observables?

Answer 14

An observable is a data source that publishes (emits) data changes.
Observers (consumers) subscribe to know whenever the data changes.

Question 15

How do components exchange information if they are not in a parent/child relationship?

Answer 15

Through Services and Subjects (a special type of observable)

Question 16

What do the built-in HttpClient’s requests return?

Answer 16

• An observable that the components can subscribe to
• The HTTP request is not sent until a component subscribes to the returned observable

Question 17

What different form-building approaches are there in Angular?

Answer 17

• Template-driven approach - easier to use but not as configurable
• Reactive approach - a bit more code but a lot more control over the developer

Question 18

What are lifecycle hooks in Angular?

Answer 18

• Directive and component instances have a lifecycle as Angular creates, updates, and destroys them
• Developers can interfere at key moments in that lifecycle by implementing one or more of the lifecycle hook interfaces
• There are 8 lifecycle hooks:
  ngOnChanges()
  ngOnInit()
  ngDoCheck()
  ngAfterContentInit()
  ngAfterContentChecked()
  ngAfterViewInit()
  ngAfterViewChecked()
  ngonDestroy()

Question 19

What are the major features of Angular?

Answer 19

declarative templates, dependency injection, end-to-end tooling