Top IONIC Interview Questions and Answers (2024)

Ionic is an open-source UI development toolkit for creating mobile, desktop, and progressive web applications with a single code base. 

Ionic is a simple and easy-to-learn framework. If you are a beginner or an experienced developer, the following ionic developer interview questions and answers can help you impress in your next Ionic interview.

1. What are the key features of Ionic?

The following are the features of Ionic:

• Cross-platform - Ionic allows developers to create cross-platform applications using a single codebase. 

• Ionic CLI helps developers by simplifying the app development process with commands for developing, testing, and deploying applications. 

• The Ionic framework provides the Cordova plugin with different components allowing you to add different features to your application.

• Framework support - Ionic supports Angular.js, Vue.js, and React.js

• With Ionic, developers can easily convert web apps into Progressive Web Apps (PWA)

2. What are observables in Ionic?

Observables are not unique to Ionic but are integral to Angular, which works closely with Ionic. Observables are powerful features that allow you to handle asynchronous operations. They provide a way to handle data streams, perform operations like mapping and filtering, and manage multiple asynchronous events.

3. What element is used as the container for an Ionic app?

App is the container element for Ionic and is created using the element tag . There should only be one element in an ionic app.

4. What is the difference between Ionic build and Ionic prepare?

Ionic build compiles and bundles the web assets and prepares them for deployment. The Ionic build uses Angular CLI. This includes converting the Typescript and other source files into JavaScript, optimizing CSS, and bundling everything to www or build directory.

Ionic prepare command prepares the project for native builds by syncing the web assets to platform-specific directories.

5. What is ion-refresher component used for in Ionic?

The ion-refresher component provides the pull-to-refresh functionality to the content component.

6. Why is the performance of Ionic bad in older Android devices?

The older Android versions used Android’s default browsers with low performance instead of modern browsers like Chrome. These older browsers lacked support for newer web standards and optimizations which affect web applications, including the ones built with Ionic.

Older WebView components had poorer performance and lacked support for many modern Javascript features and CSS capabilities which could also significantly impact the applications built using Ionic.

The older Android devices with hardware limitations like less powerful CPU, limited memory, and less advanced GPU could also affect the performance of web applications built using Ionic.

7. How do you pass data from one view to another in Ionic?

Passing data from one page to another in Ionic also depends on the version of Ionic you are working with.

If you are using Ionic 3, you can pass and receive data using the NavParams class.

If you are using Ionic 4 and later with Angular, you can pass data with Angular Router with NavigationExtras.

If you are using Ionic with React or Vue, you need to use their respective routing libraries. 

8. What are caching views in Ionic?

Caching views is an Ionic feature that caches views that have already been visited which improves the loading speed of the applications and thereby the user experience on the app.

9. What is Ionic CLI?

Ionic CLI (Command Line Interface) is a tool for developing Ionic app. YOu can install Ionic CLI using NPM.

You can install Ionic globally using the command:

npm install -g @ionic/cli

Once installed, you can create, build, and manage Ionic applications.

10. What is Capacitor by Ionic?

Capacitor by Ionic is an open-source runtime that runs Ionic apps natively on various platforms. You can create native apps for iOS, Android, and Progressive Web Apps using HTML, CSS, and JavaScript.