1 Introduction to react.js

What is React.js?

React.js is a JavaScript library that is used for building user interfaces. It was developed by Facebook and is now maintained by a community of developers. React.js is known for its ability to create reusable UI components, which makes it easier to manage complex applications. It is also known for its performance, as it uses a virtual DOM to update the UI efficiently.

How does React.js work?

React.js works by breaking down the user interface into small, reusable components. Each component has its own state and properties, which can be passed down to child components. When a component's state or properties change, React.js updates the virtual DOM and then compares it to the actual DOM. If there are any differences, React.js updates the actual DOM to reflect the changes.

Advantages of React.js

One of the main advantages of React.js is its ability to create reusable components. This makes it easier to manage complex applications, as developers can reuse components across different parts of the application. React.js is also known for its performance, as it uses a virtual DOM to update the UI efficiently. This means that only the parts of the UI that need to be updated are actually updated, which can lead to faster rendering times.

Components, State, and Props

Components are the building blocks of React.js applications. They are reusable UI elements that can be combined to create complex applications. Each component has its own state, which is an object that contains data that can change over time. Props, short for properties, are used to pass data from one component to another. They are read-only and cannot be changed by the component that receives them.

Conclusion

React.js is a powerful JavaScript library that is used for building user interfaces. It is known for its ability to create reusable components, its performance, and its use of a virtual DOM to update the UI efficiently. By breaking down the user interface into small, reusable components, React.js makes it easier to manage complex applications. Components have their own state and properties, which can be passed down to child components using props. Overall, React.js is a valuable tool for building modern web applications.

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2 Building components in react.js ⇨