Companies continue to choose React in 2023 for several reasons: 

• Large and active community:

React has a large and active community of developers who contribute to its development and provide support to others. This community ensures that React stays up to date with the latest trends in web development and provides timely updates and bug fixes.

• Reusability:

React is based on a component-based architecture that allows developers to reuse code across different parts of their application. This reduces development time and makes it easier to maintain and scale applications.

• Performance:

React’s virtual DOM efficiently updates and renders only the necessary components when there are changes, wich leads to better performance and faster load times. This makes React an ideal choice for building complex and dynamic user interfaces. 

• Scalability: 

React is highly scalable and can be used to build applications of any size. It works well with other technologies, like Redux and GraphQL, and can be easily integrated into existing systems with ease.

• Mobile-friendliness:

React can be used to build mobile applications using technologies like React Native. This allows developers to build cross-platform applications that work well on both iOS and Android devices. 

• Large companies using React:

Many large companies, like Facebook, Netflix, Airbnb, and Instagram, use React for their web applications. This provides a level of confidence to other companies in the industry that React is a reliable and powerful tool for web development.

The cost of hiring a React developer can vary depending on several factors such as location, experience, and engagement type. In general, hiring a remote React developer can be more cost-effective compared to an in-house React developer due to the lower overhead costs involved.

React developers’ rates can differ significantly across the world, with developers from Western Europe and North America commanding the highest rates, while developers from Asia, Eastern Europe, and South America are relatively cheaper. However, it’s crucial to consider the skills and expertise of a developer when making a hiring decision, as lower rates don’t necessarily guarantee quality work.

Here’s a detailed breakdown of the cost of hiring React developers based on their experience levels:

• Junior React Developers (1-2 years of experience): They are relatively new to the field, and their hourly rates can range from $30 to $50. They are usually less experienced but have a solid understanding of the fundamentals of React.

• Mid-Level React Developers (2-5 years of experience): They have gained a few years of experience and have a good understanding of React. Their hourly rates are typically between $50 and $100.

• Senior React Developers (5+ years of experience): They are highly experienced and have worked on multiple complex React projects. Their hourly rates are usually $100 or more.

It’s worth noting that some developers may charge based on the project’s scope and duration, rather than their hourly rate. Some may charge a flat rate or a percentage of the total project cost.

In addition to the developer’s experience, the location is another crucial factor that can influence the cost of hiring a React developer. The table below outlines the average hourly rates for React developers based on their location:

It’s essential to note that these rates are averages and can differ significantly based on the individual developer’s experience and skillset.

In conclusion, when hiring a React developer, it’s important to consider their experience, location, and engagement type. It’s recommended to research and compare rates from different developers and regions before making a hiring decision to ensure that you’re getting the best value for your investment.

Keys help ReactJS identify which items have changed, which terms are added, or which are removed. Keys should be given to the elements inside the array to give the elements a stable identity.

const numbers = [1, 2, 3, 4, 5];

const listItems = numbers.map((number) =>

?
<li key={number.toString()}>

  {number}

 </li>

);

When the state of your component changes, the render function will return a new tree of React elements, different to the previous/current one.

In ReactJS components, props are variables passed to it by its parent component. State although is still a variable, it is directly initialized and managed by the component. The state can also be initialized by props.

For eg. a parent component may include a child component by calling:

<ChildComponent />

The parent can pass a prop by using the syntax:

class ChildComponent extends React.Component {

 constructor(props) {

   super(props)

   console.log(props.color)

 }

}

And any other method in this class can reference the props using:

this.props.

Props can be used to set the internal state based on a prop value in the constructor:

class ChildComponent extends React.Component {

 constructor(props) {

   super(props)

   this.state.colorName = props.color

 }

}

The component can also initialize the state without looking at props.

Props should never be changed in a child component, so if there’s something going on that alters some variable, that variable should belong to the component state. In addition, props are used to allow child components to access methods that are defined in parent components. This is a means of centralizing the state management in the parent component and to avoid children having to need their own state.

Most components will simply display some sort of information based on the received props and continue to remain stateless.