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Angular 5 Interview Questions

By Umesh Singh
Last update: 16 May 2020, 7 Questions
Introduction to Angular 5

Angular is an intricate JavaScript framework. It is frequently used by developers for building hybrid mobile and web applications. The applications built on Angular 5 are very quick, light, and utterly simple to use.

The Angular 5 version also supports Typescript 2.4. The main reason for launching this version was to reduce the package size, increase rendering speed, enhance the mobile experience, and also eliminate the compiler issue present in Angular 4.

Google had also made various changes to the compiler which ultimately helped in increasing the speed of initial and incremental compilation exponentially. If you are a Javascript or Angular developer looking for a job, read these frequently asked Angular 5 Interview Questions to help you better understand the changes and the reasons behind those changes.

Most Frequently Asked Angular 5 Interview Questions And Answers

1. What are the new features rolled out in Angular 5?

The Angular 5 version consists of a bunch of new features and performance-enhancing improvements in addition to multiple bug fixes to make the coding work for Angular & Javascript Developers a lot easier than its predecessor, Angular 4. Here is a list of all the features in this version:

  • Switching to the AOT compiler by default.
  • An Integrated watch mode
  • Included type for checking in multiple templates
  • Versatile and increased flexibility of metadata
  • Removal of the *.ngfactory.ts files
  • Improved error messages for easy fixing
  • Allowing multiple exports aliases
  • New “Tree Shakeable” components section
  • Option for Hybrid Upgrade of Application
  • Updates in the I18n (Internationalization) Pipes.
2. Name the list of the building blocks of Angular?

Here is a list of the building blocks of the Angular Framework

  • Modules
  • Components
  • Templates
  • Data Binding
  • Metadata
  • Dependency Injection
  • Services
  • Directives
3. What are Event Emitters and how do they work in Angular 5?

Now, Unlike Angular 1, Angular 5 does not have a bi-directional digest cycle. In this version, any changes occurring within the component generally get propagated to all the children components present in the hierarchy through the current component.
If there is any change in one component which needs to be reflected in its parent component in the respective hierarchy, you can easily emit an event using the Event Emitter API which is native from Angular 5.
So basically, EventEmitter is defined via a class in the @angular/core module which is used equally by components and directives for emitting any custom events.

4. List the types of Data Binding supported by Angular 5?

Data Binding is the process of synchronizing the model and view to enable effective communications between the components and DOM.
In Angular 5, there are four types of Data Binding

  • Property Binding
  • Event Binding
  • Two-Way Data Binding
  • Interpolation
5. How Do We Import A Module In Angular 5?

To import a module successfully in Angular 5, we use this syntax:
import { ModuleName } from 'ModuleLocation';

6. What is the proper lifecycle hooks for the application development in Angular 5?

In Angular 5, all the components or directives have specific lifecycle events that are being managed by the @angular/core. They are used in the creation of components, rendering it, creating and rendering their children components in the hierarchy.
These components or directives process changes as and when the multiple data-bound properties have any change, and then destroy them before the removal of their templates from the DOM. Angular 5 provides a specific set of lifecycle hooks, also known as special events that are used to tap into this lifecycle while performing operations when there is a necessity.
In addition, the constructor is used to execute all the prior lifecycle events. Each and every interface comes with a single hook method prefixed with the ng. For example, the ngOnint interface has the Oninit method which needs to be implemented into the component.

7. What are the differences between Constructors and OnInit?
Constructors OnInit
It is the default method used for constructing components. It is an Angular 5 life cycle event method.
It is a TypeScript feature which is used for class instantiations It is used when there are any changes in the input or output binding values.
It is called before the ngOnInit() It is called after the constructors and the first ngOnChanges.
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