ReactJS is a JavaScript library for creating web interfaces that render dynamic content. It is used by many popular websites like Facebook and Instagram.
ReactJS developers are hard to find these days because it’s an emerging technology, but there are some common questions that companies ask in an interview to find the right fit.
This post will help you understand what should be asking and their answer, to be competitive at time of interviewing and get hired the best candidate at the company of their choice.
Top interview questions to hire ReactJS developers
What are the advantaged of React JS in development?
The key advantage of using React JS is that it is a framework for building user interfaces. It helps developers build cross-platform web applications without having to worry about the differences in browsers and devices.
React JS has been well-received by the developer community because of its performance, flexibility, and scalability. It is also considered as one of the most popular JavaScript frameworks today.
React JS allows developers to build and render the UI components in the browser rather than having to build a complete interface first then bringing it into the browser. This means that React JS takes care of updating the UI for us, so we don’t have to keep track of all updates.
What are the Limitations of React JS?
React JS has a lot of possibilities and is one of the most widely used frameworks. However, it also has its limitations that developers should be aware of.
There are two main limitations that React JS suffers from: the lack of tools, and the lack of support for mobile development.
What happens during the lifecycle of a React component?
When a developer starts developing an application, they start with setting up the file structure and importing the needed libraries. Once that is done, they start writing code. During this process, they might want to create new components in order to showcase their own skills or customize an existing one. Lastly, at some point in time, they decide it’s time to make their application live and get out there into the world!
Tell me about 5 ways that can be used Style React components?
Style React JS components are a new way to create reusable, modular pieces of CSS for front-end development.
1) Refactoring the existing interface which has a certain style to make it more consistent with your brand’s identity.
2) Creating reusable modules of styles that third-party developers can integrate into their own products without having to worry about maintaining them or updating them themselves.
3) Creating an interactive timeline application using SVG and CSS by using Style React JS Components as a template.
Most important 5 ways are:
- Inline CSS
- CSS in JS
- Styled Components
- CSS Modules
- Stylable
What is prop drilling and how can you avoid it in react js?
Prop drilling is a debugging technique that is used by developers to test their code. It consists of using props in React JS to manipulate the DOM.
Prop drilling can be avoided by changing the default behavior of a prop in React JS. For example, if you want your component to return every time, you can do this:
React.PropTypes = { getInitialState: React.PropTypes.func };
ReactDOM.render( this._state} />, document.getElementById(‘root’));
Prop drilling is a term used to describe the practice of deliberately changing the props in a React app to make it easier for you to debug. This is done by changing what the props render so that you can see what is happening. It’s sort of like stepping through the code, but only when there are no breakpoints set. You can also use prop drilling in your app while developing to ensure that your app works as expected with different props and React will help you see what changes are needed and how.
The problem with this practice is that it’s not always easy to tell if changes made have been effective or not because sometimes it doesn’t work as intended and therefore you might be wondering if anything has changed at all.
What are hooks in React?
A hook is a function that is called when an event happens on a Reactjs component. There are two types of hooks: lifecycle hooks and callback hooks. As the name implies, lifecycle hooks are called during specific phases of your component’s life cycle like beforeMount and afterRender. Callback hooks are called asynchronously – they’re not necessarily tied to a particular phase like lifecycle hooks are, but rather whenever certain actions happen on your component such as calling setState or updating props.
A hook in React js provides an easier way to render a component. They provide the functionality of taking care of all the state, lifecycle methods, as well as rendering and DOM manipulation for you.
Hooks can be rendered with two different patterns: props or context . Prop hooks look up specific properties on a component from its parent and then return them. Context hooks will receive data from this parent, which they can use to modify default behavior on the child or pass it further down if needed.
How would you optimize the performance of a React application?
However, React applications might not be performing as well as they could be. This is because there are thousands of other libraries and frameworks that have been developed to add features to a project without optimization in mind.
A powerful approach for optimizing the performance of React applications is using React-router-redux. It helps developers split up their application into different components and create better routes for specific pages or actions within an application.
How would you create Higher Order Components (HOCs) in React?
Higher Order Components (HOCs) are components that make it easier to manage state in React. They are typically used as a pattern for managing state in React apps, but they can also be used by developers outside of React apps.
How can automated tooling be used to improve the accessibility of a React application?
One of the best ways that you can use automated tooling for this is by using the Accessibility Testing Framework for Automated Web Tests (ATF). ATF takes care of testing screen readers and other assistive technologies which users might have access to on their device and making sure that your application displays correctly in their browsers.
Describe how events are handled in React
There are two ways to handle events in React. The first is to use the event object and apply handlers to it. The second is to use a callback function which is a function that will get invoked whenever an event occurs.
The first way to handle events in React is by using the event object and applying handlers to it. The event object has some predefined methods like onClick() or onChange() which can be used as handler functions. When an event happens, you get an Event object back with your handler function attached at the end of it.