Cordova

Cordova is a mobile application development framework. We’ve compiled a list of the most common and frequently asked interview questions in Cordova.

Q.1 What is Apache Cordova, and why is it used?
Apache Cordova is an open-source mobile development framework that allows developers to build cross-platform mobile applications using web technologies like HTML, CSS, and JavaScript. It's used to create native-like mobile apps for various platforms using a single codebase.
Q.2 Explain the difference between Cordova and PhoneGap.
PhoneGap is Adobe's commercial distribution of Cordova. Cordova is the open-source core, while PhoneGap adds extra tools and services on top. The core functionality and APIs are the same.
Q.3 What is a Cordova plugin, and why would you use one?
A Cordova plugin is a package of code that provides access to device features and native functionalities not available through web technologies. Developers use plugins to extend the capabilities of their Cordova apps, like accessing the camera or GPS.
Q.4 How do you create a new Cordova project?
You can create a new Cordova project using the following command: cordova create
Q.5 What is the purpose of the config.xml file in a Cordova project?
The config.xml file is used to configure various settings and preferences for a Cordova project, such as app name, version, permissions, and plugin configurations.
Q.6 Explain the Cordova build process.
The Cordova build process involves converting your web assets (HTML, CSS, JavaScript) into a native application for the target platform. This is achieved using platform-specific build tools like Xcode for iOS and Gradle for Android.
Q.7 How do you add a platform to a Cordova project?
You can add a platform using the following command: cordova platform add
Q.8 What is the purpose of the www directory in a Cordova project?
The www directory contains the web assets (HTML, CSS, JavaScript) of your Cordova app. These assets are used as the basis for building the native app for different platforms.
Q.9 Explain the role of hooks in Cordova.
Hooks in Cordova are scripts that can be executed at various points in the Cordova lifecycle, such as before or after building, adding/removing plugins, or preparing platforms. They are used for automating tasks and customizing the build process.
Q.10 What are some common challenges when debugging Cordova applications?
Common debugging challenges in Cordova include handling platform-specific issues, debugging in the WebView, dealing with plugin compatibility, and addressing performance issues.
Q.11 How do you handle different screen sizes and resolutions in a Cordova app?
Cordova allows you to use responsive design techniques like CSS media queries and viewport settings to adapt your app's layout to different screen sizes and resolutions.
Q.12 Explain the concept of Cordova's whitelist and how it affects network access.
Cordova's whitelist (Content Security Policy) is used to control which external resources your app can access. It prevents security vulnerabilities by restricting network requests to trusted domains specified in the config.xml file.
Q.13 What is the purpose of the cordova.js file in a Cordova app?
cordova.js is a JavaScript file provided by Cordova that serves as a bridge between your web app and the native APIs. It enables communication between your web code and the device's hardware and features.
Q.14 How can you handle device-specific functionality in a Cordova app?
You can use Cordova plugins to access device-specific functionality. These plugins provide JavaScript interfaces to interact with features like the camera, geolocation, and device sensors.
Q.15 Explain the Cordova release and update process for mobile apps.
The release and update process for Cordova apps involves building and testing platform-specific binaries for distribution, updating the app on app stores (e.g., Google Play Store, Apple App Store), and managing version control to track changes and bug fixes.
Q.16 What is the role of the Cordova CLI (Command-Line Interface) in the development process?
The Cordova CLI is a command-line tool used for creating, configuring, building, and managing Cordova projects. It simplifies common development tasks and interacts with various plugins and platforms.
Q.17 Explain the concept of Cordova plugins' lifecycle hooks.
Cordova plugins can define lifecycle hooks, which are functions that are automatically executed during specific events in the app's lifecycle, such as when the app is launched or paused. These hooks allow developers to perform custom actions at those times.
Q.18 How can you handle offline data storage in a Cordova app?
Cordova provides various options for offline data storage, including Web Storage (localStorage and sessionStorage), SQLite databases, and IndexedDB, depending on your application's requirements.
Q.19 What is the purpose of the Cordova SplashScreen plugin, and how do you configure it?
The SplashScreen plugin is used to display a splash screen or launch image when the app starts. You can configure it in the config.xml file, specifying the image file and duration.
Q.20 Explain the concept of Cordova's WebView and how it impacts app performance.
Cordova apps run in a WebView, which is essentially a native browser component. WebView performance can affect the overall app performance, so optimizing the HTML, CSS, and JavaScript is crucial.
Q.21 What is the Cordova Device API, and how can you use it in your app?
The Cordova Device API provides information about the device, such as its model, platform, and version. You can access this information through JavaScript to tailor your app's behavior based on the device.
Q.22 How do you handle platform-specific styling in a Cordova app?
Cordova allows you to use platform-specific CSS files and media queries to apply different styles based on the target platform, ensuring a consistent user experience.
Q.23 What is the purpose of the Cordova InAppBrowser plugin, and when would you use it?
The InAppBrowser plugin is used to display web content within a Cordova app as a separate browser window. It's commonly used for displaying external links or integrating web-based content.
Q.24 Explain the concept of Cordova's WebView security and the role of the Content Security Policy (CSP) in preventing security vulnerabilities.
Cordova's WebView enforces a security model to protect against various attacks. The Content Security Policy (CSP) is a critical part of this security model, specifying which resources can be loaded and executed in the WebView.
Q.25 What is the Cordova Geolocation API, and how can you use it to access a device's location?
The Cordova Geolocation API provides access to the device's GPS or other location services. You can use it to retrieve the device's current location coordinates, enabling location-based functionality in your app.
Q.26 Explain the Cordova File API, and how can it be used for file operations in a Cordova app?
The Cordova File API allows you to perform file-related operations, such as reading, writing, and managing files and directories on the device's file system. It's essential for handling local files and data.
Q.27 What are Cordova hooks, and how do they differ from plugin hooks?
Cordova hooks are scripts that run at predefined points in the Cordova CLI's lifecycle, while plugin hooks are specific to individual plugins. Cordova hooks apply globally to the entire project, while plugin hooks are tied to the functionality of the respective plugin.
Q.28 How can you optimize the performance of a Cordova app, especially in terms of load times and responsiveness?
Performance optimization in Cordova involves techniques like minimizing HTTP requests, optimizing images, using lazy loading, and employing efficient JavaScript coding practices to enhance load times and responsiveness.
Q.29 Explain the Cordova Camera plugin and how it can be used to capture photos or videos in a mobile app.
The Cordova Camera plugin provides access to the device's camera and allows you to capture photos or record videos from within your app. You can configure various options, such as camera quality and source selection.
Q.30 What is the Cordova Push Notification plugin, and how can you implement push notifications in your app?
The Cordova Push Notification plugin enables your app to receive push notifications from a server. You can use this plugin to implement real-time updates and notifications in your Cordova app.
Q.31 What is Cordova CLI, and why is it an essential tool in Cordova development?
Cordova CLI is a command-line tool that simplifies the process of creating, configuring, building, and managing Cordova projects. It streamlines the development workflow by providing a unified interface to perform common tasks efficiently.
Q.32 How do you check the version of Cordova CLI installed on your system?
You can check the installed Cordova CLI version by running the following command: cordova -v
Q.33 What is the command to create a new Cordova project using Cordova CLI?
To create a new Cordova project, you can use the following command: cordova create
Q.34 Explain the purpose of the config.xml file in a Cordova project and how to edit it using Cordova CLI.
The config.xml file contains project metadata and configuration settings. You can edit it using Cordova CLI with the cordova config command, such as: cordova config set
Q.35 What command is used to add a platform to a Cordova project using Cordova CLI?
You can add a platform to a Cordova project with the following command: cordova platform add
Q.36 Explain how to remove a platform from a Cordova project using Cordova CLI.
To remove a platform, you can use the following command: cordova platform remove
Q.37 How do you list the available Cordova platforms for a project using Cordova CLI?
You can list the available platforms for a project with the following command: cordova platform ls
Q.38 What is the purpose of the www directory in a Cordova project, and how can you update its contents using Cordova CLI?
The www directory contains the web assets of a Cordova app. You can update its contents using Cordova CLI by placing your HTML, CSS, and JavaScript files in this directory and then using the CLI for other project-related tasks.
Q.39 Explain the steps involved in building a Cordova project for a specific platform using Cordova CLI.
To build a Cordova project for a specific platform, follow these steps: Add the platform (if not added already): cordova platform add . Ensure your project files are up to date in the www directory. Build the project: cordova build
Q.40 What command is used to prepare a Cordova project for building using Cordova CLI?
The cordova prepare command is used to prepare a Cordova project by copying the relevant web assets and plugin files into the platform-specific project directories.
Q.41 Explain the purpose of the plugins directory in a Cordova project and how to manage plugins using Cordova CLI.
The plugins directory contains the Cordova plugins used in the project. You can manage plugins using Cordova CLI with commands like: Add a plugin: cordova plugin add . Remove a plugin: cordova plugin remove . List installed plugins: cordova plugin ls
Q.42 What is the role of Cordova hooks, and how can you manage hooks in a Cordova project using Cordova CLI?
Cordova hooks are scripts that execute at specific project lifecycle events. You can manage hooks in a Cordova project using Cordova CLI by placing your hook scripts in the hooks directory and ensuring they have executable permissions.
Q.43 How can you clean the build artifacts and temporary files in a Cordova project using Cordova CLI?
To clean the project, you can use the following command: cordova clean
Q.44 What command is used to run a Cordova app on a connected device or emulator using Cordova CLI?
You can use the cordova run command to launch the app on a connected device or emulator: cordova run
Q.45 Explain the Cordova CLI command to build a release version of an app for distribution.
To build a release version of an app for distribution, you can use the following command: cordova build --release
Q.46 What is the config.xml file in Cordova, and why is it important?
The config.xml file is a central configuration file in Cordova projects. It contains metadata, preferences, and settings for the Cordova application. It's crucial for defining how the app behaves and interacts with the device.
Q.47 What are some common elements you can find in the config.xml file, and how do they affect the Cordova app?
Common elements include , , , and . They affect the app by specifying its name, description, authorship, and various preferences such as orientation, version, and permissions.
Q.48 How can you specify the application name in the config.xml file?
You can specify the application name using the element within the element: My Cordova App
Q.49 Explain the purpose of the element in the config.xml file.
The element provides a brief description of the Cordova app, which can help users and app store listings understand its purpose and features.
Q.50 What is the significance of the element in the config.xml file, and how can it be configured?
The element specifies the app's author or creator. It can be configured as follows: Author Name
Q.51 How can you set the version of your Cordova app in the config.xml file?
The version can be set using the version attribute of the element:
Q.52 Explain the purpose of elements in the config.xml file and provide an example of how to use them.
elements allow you to configure various aspects of the app, such as orientation, permissions, and preferences. For example:
Q.53 What is the role of the element in the config.xml file, and how can it be used to control network access?
The element defines the domains or resources that the app is allowed to access. It can be used to control network access, ensuring that the app can only make requests to specified domains.
Q.54 How do you specify the icons and splash screens for different platforms in the config.xml file?
You can use the and elements to specify icons and splash screens for different platforms. For example:
Q.55 Explain the use of the element in the config.xml file.
The element is used to declare features that the app requires or uses. It helps define the set of plugins that should be installed to support these features.
Q.56 How can you specify the permissions required by your Cordova app in the config.xml file?
Permissions can be specified using the element. For example, to access the camera, you can add:
Q.57 What is the purpose of the element in the config.xml file, and how can it be used to control navigation behavior?
elements control which URLs can be loaded in the Cordova WebView. They can be used to allow or restrict navigation to specific domains.
Q.58 How do you add custom preferences and settings to the config.xml file for your Cordova app?
You can add custom preferences and settings as elements within the element, defining their name and value.
Q.59 Explain how to use variables and placeholders in the config.xml file to simplify platform-specific configuration.
You can use variables like $(VAR_NAME) in the config.xml file to simplify platform-specific configurations. For example, can be set in platform-specific .xml files.
Q.60 What is the Cordova CLI command to validate and check the syntax of the config.xml file?
To validate the config.xml file, you can use the following Cordova CLI command: cordova prepare
Q.61 What is Cordova storage, and why is it essential in mobile app development?
Cordova storage refers to the mechanisms used for data storage in Cordova applications. It is essential for maintaining app data, settings, and user-generated content across app sessions and device restarts.
Q.62 Explain the difference between local storage and session storage in Cordova.
Local storage persists data indefinitely until manually cleared or removed, even when the app is closed. Session storage, on the other hand, stores data only for the duration of a page session and is cleared when the app or page is closed.
Q.63 What is the Web Storage API, and how does Cordova utilize it for local data storage?
The Web Storage API provides a simple key-value storage mechanism in web browsers. Cordova utilizes this API to offer local data storage for mobile apps, which can be accessed using JavaScript.
Q.64 Explain the purpose of the Cordova SQLite plugin, and when would you use it for data storage?
The Cordova SQLite plugin enables developers to create and manage SQLite databases within Cordova applications. It is used when structured, relational, or large-scale data storage is required.
Q.65 How can you use the Web Storage API to store and retrieve data in a Cordova app?
You can use the localStorage and sessionStorage objects in JavaScript to store and retrieve data. For example: // Storing data - localStorage.setItem('key', 'value'); // Retrieving data - const data = localStorage.getItem('key');
Q.66 What are the advantages and limitations of using Web Storage (localStorage and sessionStorage) in Cordova apps?
Advantages include simplicity, ease of use, and support for most data types. Limitations include storage size limitations (usually around 5-10 MB), lack of structured storage, and data not persisting through app uninstallation.
Q.67 Explain the basic steps to use the Cordova SQLite plugin for data storage in a Cordova app.
To use the Cordova SQLite plugin, you typically follow these steps: Install the plugin: cordova plugin add cordova-sqlite-storage. Open or create a database. Execute SQL queries for data manipulation. Handle errors and results.
Q.68 What is the purpose of the Cordova File plugin, and how can it be used for file-based storage in Cordova apps?
The Cordova File plugin allows you to access and manipulate files and directories on the device's file system. It can be used for file-based storage, such as saving images, documents, or app-specific files.
Q.69 Explain the use of the Cordova File Transfer plugin for downloading and uploading files in a Cordova app.
The Cordova File Transfer plugin facilitates downloading and uploading files to and from remote servers. It provides methods to initiate and manage file transfers in Cordova applications.
Q.70 How can you securely store sensitive data, such as API keys or passwords, in a Cordova app?
Sensitive data should be stored securely using techniques like encryption or using Cordova's secure storage plugins. Plugins like Cordova Secure Storage provide a secure way to store sensitive data.
Q.71 What is Cordova's LocalForage library, and how does it simplify data storage in Cordova apps?
LocalForage is a JavaScript library that provides a simple and consistent API for asynchronous storage. It abstracts various storage mechanisms (such as IndexedDB, WebSQL, and localStorage) and simplifies data storage in Cordova apps.
Q.72 How do you handle data synchronization and conflict resolution in a Cordova app with offline capabilities?
Data synchronization and conflict resolution can be implemented using custom logic or third-party libraries like PouchDB and Couchbase Mobile. These libraries allow for seamless synchronization of data between the app and backend servers.
Q.73 Explain the Cordova File Opener plugin and its use in handling file types in a Cordova app.
The Cordova File Opener plugin allows you to open files with the appropriate native application on the device. It is used for handling various file types, such as PDFs, images, and documents, by launching the default viewer.
Q.74 What are some best practices for optimizing data storage and access performance in Cordova apps?
Best practices include optimizing database queries, using indexes, caching frequently accessed data, managing data lifecycle, and minimizing disk I/O to improve data storage and access performance.
Q.75 How can you ensure data backup and restoration in a Cordova app, especially when migrating or reinstalling the app?
To ensure data backup and restoration, you can implement a backup and restore feature within the app using a cloud-based solution or by exporting and importing data to/from a file stored on the device's file system.
Q.76 What is Cordova Plugman, and what role does it play in Cordova development?
Cordova Plugman is a command-line tool used to install, manage, and remove Cordova plugins in a Cordova project. It helps streamline the process of adding and managing plugins.
Q.77 How can you install Cordova Plugman on your development environment?
Cordova Plugman is included with the Cordova CLI, so you don't need to install it separately. You can use it directly from the Cordova CLI.
Q.78 Explain the basic command to add a Cordova plugin to a project using Cordova Plugman.
To add a Cordova plugin using Plugman, you can use the following command: cordova plugin add
Q.79 What is the purpose of the plugman.json file in a Cordova plugin, and how does it relate to Cordova Plugman?
The plugman.json file is used to specify plugin metadata, such as plugin ID, version, and platform-specific details. Cordova Plugman uses this file to correctly install and configure the plugin in a project.
Q.80 Explain the difference between Cordova CLI's plugin management and Cordova Plugman.
Cordova CLI provides a higher-level interface for managing plugins and abstracts many of the details. Cordova Plugman is a lower-level tool that directly manipulates the plugin files, allowing for more granular control.
Q.81 What is the significance of the plugin.xml file in a Cordova plugin, and how does Cordova Plugman use it?
The plugin.xml file is the plugin's configuration file, containing metadata, platform-specific hooks, and preferences. Cordova Plugman uses it to install and configure the plugin for different platforms.
Q.82 How do you remove a Cordova plugin from a project using Cordova Plugman?
To remove a Cordova plugin using Plugman, you can use the following command: cordova plugin remove
Q.83 Explain how to list the installed Cordova plugins for a project using Cordova Plugman.
To list the installed Cordova plugins for a project, you can use the following command: cordova plugin ls
Q.84 What is the role of the platforms directory in a Cordova project, and how does Cordova Plugman interact with it when installing plugins?
The platforms directory contains platform-specific project files. Cordova Plugman copies plugin files into the respective platform directories during the installation process.
Q.85 Can you use Cordova Plugman to update the versions of installed plugins in a project? If so, how?
Yes, you can use Cordova Plugman to update the versions of installed plugins. To do so, simply re-add the plugin with the desired version using the cordova plugin add command.
Q.86 Explain how Cordova Plugman handles platform-specific nuances when installing plugins.
Cordova Plugman is responsible for copying platform-specific files and making necessary adjustments specified in the plugin's plugin.xml file. This allows plugins to function correctly on each platform.
Q.87 What are Cordova plugin hooks, and how do they relate to Cordova Plugman?
Cordova plugin hooks are scripts that execute at specific points during the plugin installation process. Cordova Plugman triggers these hooks based on the plugin's plugin.xml configuration, allowing developers to perform custom actions during installation.
Q.88 How can you troubleshoot plugin installation issues using Cordova Plugman?
To troubleshoot plugin installation issues, you can check the plugin's plugin.xml file for any errors, review the Cordova CLI's output for error messages, and ensure that you have the required dependencies installed for the plugin.
Q.89 What is the significance of the cordova_plugins.js file generated by Cordova Plugman, and how is it used in Cordova apps?
The cordova_plugins.js file is generated by Cordova Plugman and is used to map plugin JavaScript files to their respective Cordova JavaScript interfaces. It ensures that the Cordova app can access the plugin's functionality.
Q.90 Explain the process of manually editing plugin files in a Cordova project when necessary, and how does Cordova Plugman handle these changes during updates?
When editing plugin files manually, you should be cautious to preserve your changes. During plugin updates using Cordova Plugman, the tool attempts to retain custom changes by using merge strategies defined in the plugin's plugin.xml file. However, conflicts may arise, and manual intervention may be required to resolve them.
Q.91 What is a Cordova plugin, and why would you develop one for a Cordova app?
A Cordova plugin is a package of code that provides access to device features or native functionalities not available through web technologies. Developers create plugins to extend the capabilities of Cordova apps by interfacing with native code.
Q.92 What are the key components of a Cordova plugin?
A Cordova plugin typically consists of JavaScript files, a plugin.xml configuration file, platform-specific source files, and potentially other assets or resources required for the plugin's functionality.
Q.93 Explain the role of the plugin.xml file in a Cordova plugin.
The plugin.xml file is the plugin's configuration file. It contains metadata, platform-specific details, hooks, and preferences required for the plugin to be installed and used within Cordova projects.
Q.94 What is the structure of a Cordova plugin, and how does it vary across different platforms?
A Cordova plugin's structure typically includes a top-level directory with the plugin's JavaScript files, a plugin.xml file, and platform-specific directories (e.g., src/ios, src/android) containing platform-specific source code files.
Q.95 How can you create a new Cordova plugin from scratch?
To create a new Cordova plugin, you can use the Cordova CLI's cordova plugin create command, specifying the plugin's ID and name: cordova plugin create --name
Q.96 What is the purpose of the www directory within a Cordova plugin?
The www directory in a Cordova plugin is where you place JavaScript files that expose the plugin's API to Cordova applications. These files are typically included in the Cordova app when the plugin is installed.
Q.97 Explain how to define and use custom Cordova plugin APIs within JavaScript code.
Custom Cordova plugin APIs are defined in JavaScript files within the www directory. They are typically used by including the plugin in a Cordova project and accessing the defined API methods through JavaScript.
Q.98 What are Cordova plugin hooks, and how can they be used in plugin development?
Cordova plugin hooks are scripts that execute at specific points during the plugin installation process. Plugin developers can use hooks to perform custom actions during installation, such as copying files or configuring platform-specific settings.
Q.99 How can you test a Cordova plugin during development before publishing it to a package manager or repository?
You can test a Cordova plugin during development by creating a local development project and installing the plugin directly from your local file system. This allows you to iterate and test the plugin's functionality.
Q.100 Explain the process of debugging Cordova plugins, especially when dealing with platform-specific code.
Debugging Cordova plugins involves inspecting and debugging platform-specific code. Developers can use native debugging tools, log messages, and Cordova's plugin-test framework to troubleshoot and fix issues.
Q.101 What are some best practices for writing efficient and cross-platform Cordova plugins?
Best practices include providing consistent and well-documented APIs, handling asynchronous operations properly, adhering to platform-specific guidelines, and thoroughly testing on various devices and platforms.
Q.102 How can you publish a Cordova plugin to a package manager or repository for other developers to use?
To publish a Cordova plugin, you can create a package (e.g., npm package for JavaScript-based plugins) and make it available on a package manager like npm or upload it to a public repository. Developers can then install it using the Cordova CLI.
Q.103 Explain the concept of Cordova plugin versioning and how it impacts plugin development and maintenance.
Cordova plugin versioning allows developers to release updates and improvements to plugins while ensuring compatibility with existing applications. Semantic versioning (SemVer) is commonly used to communicate version changes.
Q.104 What are some common security considerations when developing Cordova plugins, especially when accessing device features or native APIs?
Security considerations include validating user inputs, using platform security features, handling sensitive data securely, and adhering to permissions and policies for accessing device features.
Q.105 How can you handle platform-specific nuances and differences in Cordova plugin development to ensure consistent behavior across different mobile platforms?
To handle platform-specific nuances, developers can use conditional code blocks and leverage the platforms directory structure within the plugin. Additionally, thorough testing on each platform is essential to ensure consistent behavior.
Q.106 Which API method returns the value associated with the key?
localStorage.getItem()
Q.107 What are the prerequisites for embedding a WebView?
Prerequisites for embedding a WebView are: 1. Cordova 3.3.0 or greater 2. Android SDK updated to the latest SDK 3. Amazon WebView SDK
Q.108 Which operating systems are supported by Android SDK?
Linux, Windows, OS X are supported by Android SDK.
Q.109 Which command is used by Plugman to set the URL of the current plugin registry that plugman is using?
plugman config set registry
Q.110 What is Data subject?
Data subject refers to an identified or identifiable individual to whom personal information relates, whether such identification is direct or indirect (like, by reference to an identification number or to one or more factors specific to physical, physiological, mental, economic, cultural or social identity).
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