Angular Interview Questions and Answers
Question - 71 : - What are some features of Angular 7?
Answer - 71 : -
Unlike the previous versions of Angular, the 7th major release comes with the splitting of @angular/core. This is done in order to reduce the size. Not every module is required by an Angular developer. Therefore, in Angular 7 each split of the @angular/core will have no more than 418 modules.
Angular 7 features drag-and-drop and virtual scrolling. Lastly, it also has a new and enhanced version of the ng-compiler.
Question - 72 : - What is string interpolation in Angular?
Answer - 72 : -
Also referred to as mustache syntax, string interpolation in Angular refers to a special type of syntax that makes use of template expressions in order to display the component data. These template expressions are enclosed within double curly braces i.e. {{ }}.
The JavaScript expressions that are to be executed by Angular are added within the curly braces and the corresponding output is embedded into the HTML code. Typically, these expressions are updated and registered like watches as a part of the digest cycle.
Question - 73 : - Explain Angular Authentication and Authorization.
Answer - 73 : -
The user login credentials are passed to an authenticated API, which is present on the server. Post-server-side validation of the credentials, a JWT (JSON Web Token) is returned. The JWT has information or attributes regarding the current user. The user is then identified with the given JWT. This is called authentication.
Post logging in successfully, different users have different levels of access. While some may access everything, access for others might be restricted to only some resources. The level of access is authorization.
Question - 74 : - How to generate a class in Angular 7 using CLI?
Answer - 74 : -
ng generate classDummy [options]
This will generate a class named Dummy.
Question - 75 : - Explain what is the difference between Angular and Backbone.js?
Answer - 75 : -
The following are the differences between Angular and Backbone.js
- Architecture: Backbone.js makes use of the MVP architecture and doesn’t offer any data binding process. Angular works on the MVC architecture and makes use of two-way data binding for driving application activity.
- Community Support: Being backed by Google greatly ups the community support received by the Angular framework. Extensive documentation is also available. Although Backbone.js has some community support, it only documents on Underscore.js templates, not much else.
- Data Binding: Angular uses a two-way data binding process and thus is a bit complex. Backbone.js doesn’t have any data binding process and thus has a simplistic API.
- DOM: The prime focus of Angular JS is on valid HTML and dynamic elements that imitate the underlying data for rebuilding the DOM as per the specified rules and then works on the updated data records. Backbone.js follows the direct DOM manipulation approach for representing data and application architecture changes.
- Performance: Thanks to its two-way data binding functionality, Angular offers an impactful performance for both small and large projects. Backbone.js has a significant upper hand in performance over Angular in small data sets or small webpages.
- Templating: Angular supports templating via dynamic HTML attributes. These are added to the document to develop an easy-to-understand application at a functional level. Unlike Angular, Backbone.js uses Underscore.js templates that aren’t fully featured as Angular templates.
- The Approach to Testing: The approach to testing varies greatly between Angular and Backbone.js due to the fact that while the former is preferred for building large applications the latter is ideal for developing smaller webpages or applications. For Angular, unit testing is preferred and the testing process is smoother through the framework. In the case of Backbone.js, the absence of a data binding process allows for a swift testing experience for a single page and small applications.
- Type: Angular is an open-source JS-based front-end web application framework that extends HTML with new attributes. On the other hand, Backbone.js is a lightweight JavaScript library featuring a RESTful JSON interface and MVP framework.
Question - 76 : - What are templates in Angular?
Answer - 76 : -
Written in HTML, templates in Angular contain Angular-specific attributes and elements. Combined with information coming from the controller and model, templates are then further rendered to cater to the user with the dynamic view.
Question - 77 : - Explain the difference between an Annotation and a Decorator in Angular.
Answer - 77 : -
In Angular, annotations are used for creating an annotation array. They are the only metadata set of the class using the Reflect Metadata library.
Decorators in Angular are design patterns used for separating decoration or modification of some class without changing the original source code.
Question - 78 : - What are directives in Angular?
Answer - 78 : -
Directives are one of the core features of Angular. They allow a developer to write new, application-specific HTML syntax. In actuality, directives are functions that are executed by the Angular compiler when the same finds them in the DOM. Directives are of three types:
- Attribute Directives
- Component Directives
- Structural Directives
Question - 79 : - What are the differences between Angular and jQuery?
Answer - 79 : -
The single biggest difference between Angular and jQuery is that while the former is a JS frontend framework, the latter is a JS library. Despite this, there are some similarities between the two, such as both features DOM manipulation and provide support for animation.
Nonetheless, notable differences between Angular and jQuery are:
- Angular has two-way data binding, jQuery does not
- Angular provides support for RESTful API while jQuery doesn’t
- jQuery doesn’t offer deep linking routing though Angular supports it
- There is no form validation in jQuery whereas it is present in Angular
Question - 80 : - Could you explain the difference between Angular expressions and JavaScript expressions?
Answer - 80 : -
Although both Angular expressions and JavaScript expressions can contain literals, operators, and variables, there are some notable dissimilarities between the two. Important differences between Angular expressions and JavaScript expressions are enlisted below:
- Angular expressions support filters while JavaScript expressions do not.
- It is possible to write Angular expressions inside the HTML tags. JavaScript expressions, contrarily, can’t be written inside the HTML tags.
- While JavaScript expressions support conditionals, exceptions, and loops, Angular expressions don’t.