Binaryveda 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

Closures are functions that have access to their own scope and the scope of their outer function. Currying is the process of converting a function that takes multiple arguments into a sequence of functions that each take a single argument.

• Closures allow functions to retain access to variables from their containing scope even after the outer function has finished executing.

• Currying allows for partial application of a fu...read more

Higher order components are functions that take a component and return a new component with additional functionality.

• Higher order components allow code reuse and logic sharing between components.

• They are commonly used for adding props, state, or lifecycle methods to components.

• Example: withAuth HOC can add authentication logic to a component.

Lexical scope refers to the visibility of variables within a specific block of code.

• Variables declared inside a function are only accessible within that function's scope.

• Nested functions have access to variables declared in their outer function's scope.

• Lexical scoping allows for closures, where inner functions retain access to outer function's variables even after the outer function has finished executing.

Hooks are functions that let you use state and other React features in functional components. useRef hook is used to persist a value between renders without causing a re-render.

• Hooks are introduced in React 16.8 to allow state and lifecycle features in functional components.

• useRef hook is used to persist a mutable value that won't trigger a re-render when changed.

• It is commonly used to access DOM elements or store muta...read more