Top 16 Ionic Interview Questions & Answers

Ionic framework is the first choice for businesses to develop applications that can work seamlessly on multiple platforms. The demand for Ionic developers is increasing, but to find a high-paying job, the developers must establish their knowledge.

To prepare for an interview for an Ionic developer, you need to learn the most common Ionic interview questions and answers. Good preparation will certainly help you get your dream job as an Ionic developer.

Ionic Interview Questions and Answers

1. What makes Ionic the best framework in the market?

Ans. The Ionic framework offers multiple features, making it highly suitable to develop targeted apps for businesses.

  • Support for multiple platforms: Applications developed using Ionic framework technology is easily deployed across iOS, Android, and desktop platforms from one codebase. Ionic applications are written only once to run on any device.
  • Standard and reliable web technologies: Standard and reliable web technologies such as CSS, HTML, and JavaScript form the basis of the Ionic framework, allowing Ionic applications to have consistent API. These applications can be run easily on multiple platforms.
  • Availability of pre-designed components: Ionic framework comes with basic themes, pre-designed components, and typography for quick and easy development of Ionic applications.
  • Cordova plugin: This facilitates the call of native device functions directly from JavaScript code through API.
  • Open-source framework: The Ionic framework is an open-source project with an MIT license. Developers can use the framework to develop personal and business solutions without worrying about the cost of the framework. It also allows developers to develop and extend as many features as possible.
  • Ionic CLI: The Command Line Interface (CLI) facilitates developers to develop and emulate Ionic applications.
  • Compatibility: Angular framework was originally used with older editions. Recent editions of Ionic support various front-end frameworks.
  • Inclusion of JavaScript components: Support for JavaScript components enables functionality that can’t be designed with just HTML and CSS.
  • Primary Angular support: The decentralized framework became popular because of its seamless integration with the Angular ecosystem. Integrated with the Angular core libraries, it caters to the demands of Angular developers.

2. What is the latest released Ionic version? What can you expect from it?

Ionic 6 is the latest version of the Ionic framework launched in December 2021. It has the following new features:

  • Quick upgrade: With fewer breaking changes than releases 4 and 5, Ionic 6 is easier to migrate.
  • Reliable release cadence: The release schedule is modified to correlate with Android and iOS releases. This makes it easier to introduce major yearly releases of the Ionic framework.
  • iOS design changes: For iOS mode, refresher style, updated toolbar, and dark mode modal styles are introduced. A newer collapse option is included to the ion-footer and ion-header to hide both header and footer until the user scrolls.
  • Android material design changes: Filled and outline variants support for Android material design are introduced in Ionic 6. Ion-select enables the popover interface now. The newer version supports error and helper text slots, apart from the character counter.
  • Newer component features: New components are added to update the bottom sheet, DateTime, select, model, and popover.
  • Introduction of new components: Accordion component ion-accordion organizes large content volumes. Ion-breadcrumbs are useful in knowing the context.
  • Improvements to Stencil: Performance and building changes to Stencil make it possible to run Ionic apps similar to native applications.
  • New custom elements build: New Custom Elements build is rolled out to enable you to include only the essential components in the application. This helps overcome the lazy load time of Stencil.
  • Newer options to build apps: Now, Ionic version 6 can be used with Vite, Rollup, and ESbuild, giving more options for developers to build new apps.
  • Vue routing feature: UseIonRouter injectable allows developers to retain control with respect to page transitions.
  • New platform detection customization options: Ionic 6 framework now supports devices that don’t fall into pre-configured platform containers.
  • New improvements to TypeScript: TypeScript interfaces are modified to remove previous errors.

3. How to deal with CORS?

Ans. The cross-origin resource sharing (CORS) uses additional HTTP headers to notify browsers to allow a web application to access specific resources from an origin different from the current running origin. The CORS standard gives permission asset access to servers. To enhance security, browsers restrict CORS requests initiated within the scripts. The server handles CORS access. The server app can be modified with CORS response headers to allow resource access for the client app.

4. How will you reduce the size of your Ionic application’s APK?

Ans. The Size of the Ionic app can be controlled by removing unwanted components. Size reduction can be done in the following steps.

Step 1: Delete unwanted icons and compress all screenshots.

Step 2: Minify JS and CSS files and change the index.html file.

Step 3: Remove unused Cordova plugins and external models and unnecessary code.

Step 4: Run Ionic build Android-prod command to further reduce the app size.

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

Ans. Here are the differences between ionic prepare and build:

  • Ionic prepare: Copies all files from www folder to www folder in the target platform
  • Ionic build: After doing Ionic prepare activities, it builds the source code of the app to enable the app to run on an emulator.

6. What is a progressive web app?

Ans. A web app developed and designed to look and feel like native phone apps is called a progressive web app. It gives a user experience of feeling like using one of the native mobile apps. These apps are easily deployed to servers, accessed using URLs, and effectively indexed by search engines. The latest Ionic version 6 makes developing faster, reliable, and re-engageable progressive web apps much easier.

7. Which IDE is suitable for Ionic mobile application development?

Ans. Visual studio, WebStrom, and Atom are some of the popular IDEs suitable for Ionic application development.

8. List the page lifecycle events in Ionic.

Ans. Below is a list of page lifecycle events:

  • ngOnInit: Fired once during initialization of the component
  • ngOnDestroy: First before Angular removes the view.
  • ionViewWillEnter: Fired when routing-to component is likely to animate into view
  • ionViewWillLeave: Fired when routing-from component will start animating.
  • ionViewDidLeave: Fired when routing-to component has finished animating

9. How to debug apps while testing on emulators or real devices?

Ans. Chrome remote debugging is useful to test issues of the app. Remote debugging tools from Mac, Linux, or Windows are useful in debugging on android device simulators. Safari debugging tool is useful for debugging on the iOS application simulator.

10. How to pass data from one view of the Ionic application to another?

Ans. Angular JS and UI router are used in the Ionic framework. Angular services data are accessed using resolve configuration. UI-router also has to resolve configuration for this purpose. Resolve is better than stateful services as it allows better testing.

11. How to render a huge list with like 3000 items in Ionic without affecting scroll performance?

Ans. The collection-repeat directive only renders visible items of the DOM. So, even 3000 items huge list won’t affect scroll performance as visible items in the viewport alone are rendered.

12. Why is caching the views important in Ionic apps?

Ans. By default, Ionic caches a maximum of ten views. It improves performance as it stores multiple states of views at the same time. Cache: false in UI-router state config disables caching. Globally, caching can be disabled by setting maxCache derivative to zero.

13. How to access mobile phone native functions in Ionic applications?

Ans. The native mobile phone apps are not available out of the box in the Ionic framework. However, the plugin architecture of Cordova enables the use of Angular Wrappers using ngCordova, which can be used to load and use native mobile applications. The plugin must be installed first using the install<plugin name> command.

14. How to deploy an Ionic project onto a device?

Ans. On Android devices, enable USB debugging and developer mode. Then using the command line, run Ionic Cordova run Android–device.

15. How is Ionic better than Cordova if Ionic is based on Cordova?

Ans. Cordova allows the creation of native applications for various mobile platforms using HTML, CSS, and JavaScript. Ionic enables hybrid development of mobile apps using HTML, CSS, and JavaScript that, can be easily deployed through open-source Cordova architecture. With Ionic commands, you can use additional packages along with any Cordova plugin. Ionic framework eases the development process with slick UI and UX. The ionic framework allows you to test the mobile app from the initial www folder without having to create an app build. Ionic code creates better performing applications taking advantage of quicker jqLite needing minimal DOM manipulation and native hardware acceleration.

16. How to secure your Ionic mobile app?

Ans. Any mobile app open to the public is prone to hacker attacks. Some additional steps make it difficult for hackers to crack the code. Using HTTPS instead of HTTP, SSL pinning connection, using code obfuscator along with building using ‘prod’ and ‘release’ keywords to automatically uglify the code, securing local storage using Ionic team services or third party providers, and moving sensitive operations to the server instead of running those in-house.

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