Essentially, React is a JavaScript library that helps developers build user interfaces (UIs). For websites and web apps, UIs are important because they consist of the elements that allow sites to be user-friendly. Elements such as menus, search bars, buttons, etc. Before hiring a ReactJS developer, you need to know what makes it different from other options.
For instance, take a moment and think about this: Why are UIs relevant for websites? Do they make a difference? It might seem like just a simple term, and you might be thinking: “Okay yeah, it helps users understand better the website, but are UIs that crucial?” Well, YES!!! Imagine pouring so much sweat and tears into your business and having a website looking like this:
Probably you’ve encountered websites like these and didn’t even spend a minute on them. But thankfully, ReactJS developers have come to the rescue with the ability to create beautiful, user-friendly, and attractive sites for your customers to stick around.
Facts about ReactJS
- ReactJS is maintained mainly by Facebook and a community of individual developers and companies.
- ReactJS offers more stable code because it uses downward data flow only. The main reason behind this is that when changes occur in the small structure, the big structure is not affected.
- Many Fortune 500 companies use the ReactJS library. Companies like Netflix, American Express, New York Times, Coursera, and Chrysler are a but a few among them.
- React uses a virtual DOM instead of the real DOM. This means that a web page no longer recalculates every time the DOM changes browser. With the virtual DOM, whenever changes occur, a new virtual DOM representation of the UI is created. This makes the website look cleaner and perform better.
What Does a React Developer do?
- Create interactive UIs with more predictable views that are simpler to debug. React updates efficiently to your developer’s designed views for each state in the application, appropriately rendering the correct components with the data changes.
- Because the React library is component-based, developers can build encapsulated components that manage their own state, then compose them to make complex UIs. Additionally, it’s simpler to pass data throughout the application and keep state out of the DOM.
- Develop new features without needing to rewrite the existing code.
- Manipulate the state passed to the ReactJS view to understand the output fully and triggered actions, events, and more.
- Create bug-free applications and customized plug-ins and modules.
- Develop and maintain websites. If they are React native developers, they can create and maintain the front-end of a mobile application.
Top ReactJS Interview Questions
Before you hire a ReactJS developer, you need to know that they genuinely understand the library. If you already made up your mind that you need a React developer in your team but are frustrated for not finding the talent you need – contact us, we will help you hire the perfect candidate or check the complete list with top questions you should ask your future developer if you want to do the screening on your own.
Here are 4 questions that will help you identify if the candidate is a skilled ReactJS developer.
1. Name and explain the different lifecycle methods
To help guarantee that your potential developer has experience with React, check to make sure they know the diverse lifecycle methods:
- componentWillMount – commonly used for App configuration in the root component
- componentDidMount – perform setup that wouldn’t be possible without a DOM and start receiving all the necessary data
- componentWillReceiveProps – this method changes trigger state transitions based on particular prop changes
- shouldComponentUpdate – helps improve performance by preventing a rerender if a component receives a new prop. shouldComponentUpdate returns a boolean to determine whether or not the component is rerendered
- componentWillUpdate – this isn’t often used, but some developers like to use it in place of componentWillReceiveProps on components that also have shouldComponentUpdate without access to previous props
- componentDidUpdate – used to update the DOM in response to prop or state changes
- componentWillUnmount – cancel outgoing network requests or remove all event listeners associated with the component
2. Explain and give an example of a Simple Component and a Stateful Component
React components implement a render() method that takes input data and returns what to display. In the example given by React, it uses an XML-like syntax called JSX. The input data passed into the component can be accessed using render() via this.props. Here’s an example of a simple component:
class HelloMessage extends React.Component {
renter() {
return (
<div>
Hello {this.props.name}
</div>
);
}
}
ReactDOM.render(
<HelloMessage name=”Taylor” />,
);A stateful component, in addition to taking input data, can maintain internal state data that can be accessed via this.state. When a component’s state data changes, the rendered markup will be updated by re-invoking render().
3. Explain the difference between state and props in ReactJS
Props, short for properties, are similar to an argument that is passed to a pure JavaScript function. They are considered immutable and should not change through a component’s lifecycle. They can be accessed via this.props. Let’s look at an example:
import React from ‘react’;
class Welcome extends React.Component {
renter() {
return <h1>Hello {this.props.name}</h1>;
}
}
const element = ;State, instead, are used to create dynamic and interactive components in React. State determines exactly how a component renders and behaves. Let’s look at a simple state example:
import React from ‘react’;
class Button extends React.Component {
constructor() {
super();
this.state = {
count: 0,
};
}
updateCount() {
this.setState((prevState, props) => {
return { count: prevState.count +1 }
});
}
render() {
return (<button
onClick={() => this.updateCount()}
>
Clicked {this.state.count} times
</button>);
}
}
export default Button;
4. Where should you make an AJAX request?
You should make an AJAX request in a React component in componentDidMount. This method is executed when the component is added to the DOM, or mounts, for the first time, so it’s only executed once throughout the component’s life. Developers can’t guarantee that the AJAX request will have resolved before the component mounts, meaning that they could be trying to setState on an unmounted component, leading to errors. Making the request in componentDidMount, though, will make sure there’s a component to update.
How to Hire a React Developer?
This are 5 strategies to help you hire talented React developers:
- Social Media: Social platforms like Facebook, LinkedIn, Quora, and Twitter have many talented developers searching for jobs. However, although there is a high job demand, you need to have time to headhunt, recruit, and interview.
- Freelancing Platforms: Freelancers are a great option if you want to hire an employee for a single project or a specific task. However, freelancing platforms tend to be chaotic, and there is no vetting, so it’s hard to identify which candidate will be the best fit. Plus, if you are looking for committed employees, freelancers are not the best option, because they are always seeking for more opportunities.
- Local Recruitment Agencies: These agencies do all the job for you. They know the local market, so they know how to find the type of candidate you want in your team. The downside is that because they are local, their talent pool is reduced. And most of them are not specialized in hiring tech talent, meaning that they don’t have the necessary knowledge when it comes to hiring the best developer.
- Job Boards: You post a job description with the type of candidate you are trying to find, and hopefully, developers interested in the opportunity reach out to you with their CVs and portfolio. However, despite job boards being a good hiring option, there is no vetting. So this process might be very time consuming, involving a lot of interviews with candidates that might not even read the job description thoroughly.
- Remote Recruitment Agencies: These types of agencies work similarly to local recruitment agencies. However, they don’t focus on searching for talent in just one area. Such agencies have the entire world to headhunt for talented remote React developers. And the best thing about remote recruitment agencies? They are specialized in tech talent. This means that you’ll not only find candidates who will accept lower salaries due to their reduced cost of living, but you’ll also know that these candidates were recruited by IT experts: people who know what questions to ask.
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