CNV Labs and Technologies React Native Developer Interview Questions and Answers

Component life cycle in React refers to the series of methods that are invoked at different stages of a component's existence.

• Mounting: constructor, render, componentDidMount

• Updating: render, componentDidUpdate

• Unmounting: componentWillUnmount

Code quality is maintained through code reviews, automated testing, coding standards, and continuous integration.

• Regular code reviews by peers to catch errors and ensure best practices are followed

• Implementing automated testing to catch bugs early in the development process

• Enforcing coding standards and guidelines to maintain consistency and readability

• Utilizing continuous integration tools to automate the build and te

The possible values of a and b that satisfy the equation a*b = 104.

• Possible values of a and b are (1, 104) and (104, 1).

• Factors of 104 are (1, 104), (2, 52), (4, 26), (8, 13).

A simple program that prints 'Hello, World!' in Java.

• Create a class with a main method.

• Use System.out.println() to print 'Hello, World!'.

Functional components are stateless and use functional programming concepts, while class components are stateful and use object-oriented programming concepts.

• Functional components are simpler and easier to read and test.

• Class components have access to lifecycle methods and state.

• Functional components are preferred for simple UI components, while class components are preferred for complex UI components.

• Functional compon...read more

Yes, I have worked on native components.

• I have experience in creating custom native modules for React Native apps.

• I have integrated native libraries like Firebase, Google Maps, and Camera into React Native apps.

• I have used native UI components like TextInput, ScrollView, and FlatList in React Native apps.

• I have also worked with native modules for iOS and Android separately.

Hooks are functions that allow you to use state and other React features without writing a class.

• useState() - for managing state in functional components

• useEffect() - for performing side effects in functional components

• useContext() - for consuming context in functional components

• useReducer() - for managing complex state in functional components

• useCallback() - for memoizing functions in functional components

Hermes is a JavaScript engine optimized for React Native apps.

• Developed by Facebook to improve app startup time and reduce memory usage.

• Uses ahead-of-time compilation to convert JavaScript code into bytecode.

• Supports ES6 syntax and is compatible with most React Native libraries.

• Can be enabled in React Native projects by adding a single line to the configuration file.

Yes, I am familiar with the new architecture of React Native.

• The new architecture of React Native is based on Fabric, a C++ UI framework.

• It separates the UI rendering from the JavaScript thread, resulting in improved performance.

• It also introduces new features like TurboModules and JSI for better native module integration.

• The new architecture is being gradually rolled out in React Native releases.

• It requires some chang...read more

The difference between == and === is that == compares values after type coercion while === compares values and types.

• The double equals (==) operator compares values after type coercion.

• The triple equals (===) operator compares values and types.

• Type coercion is the process of converting one data type to another.

• Type coercion can lead to unexpected results.

• For example, 1 == '1' is true because the string '1' is coerced t...read more

Concurrency in Swift can be handled using Grand Central Dispatch (GCD) and Operation Queues.

• Use GCD to perform tasks concurrently by creating dispatch queues.

• Use Operation Queues to manage and execute multiple operations concurrently.

• Avoid race conditions by using serial queues or synchronization techniques like semaphores or locks.

iOS app distribution methods include App Store, Ad Hoc, Enterprise, and TestFlight.

• App Store distribution is for public release and requires Apple's review process.

• Ad Hoc distribution allows sharing apps with a limited number of devices.

• Enterprise distribution is for in-house apps within a company.

• TestFlight is for beta testing with external testers before App Store release.

MVVM (Model-View-ViewModel) is a design pattern used in Swift to separate the user interface logic from the business logic.

• MVVM divides the code into three main components: Model, View, and ViewModel.

• Model represents the data and business logic of the application.

• View displays the data and interacts with the user.

• ViewModel acts as a mediator between the Model and View, handling the logic for the View.

• MVVM helps in maki...read more

Multithreading is the ability of a CPU to execute multiple threads concurrently, allowing for improved performance and responsiveness in applications.

• Multithreading allows multiple tasks to be executed simultaneously on a single CPU core.

• It can improve performance by utilizing idle CPU time for other tasks.

• Examples include running background tasks while the main thread handles user interactions in an iOS app.

I have worked on various projects ranging from e-commerce apps to social networking platforms.

• Developed a mobile e-commerce app using React Native, integrating with backend APIs for product listings and user authentication

• Built a social networking platform with real-time messaging functionality using Firebase and Redux for state management

• Optimized app performance by implementing code splitting and lazy loading techniq

Yes, I have experience handling a team in previous projects.

• Led a team of developers in a project to develop a React Native app

• Assigned tasks, set deadlines, and ensured team members were on track

• Conducted regular team meetings to discuss progress and address any issues

• Provided guidance and support to team members to help them succeed

• Collaborated with other teams to ensure smooth project delivery