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React Basic Tutorial


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React Tutorial

This is the React comment box example from the React tutorial.

React is a JavaScript library for building user interfaces.

  • Declarative: React makes it painless to create interactive UIs. Design simple views for each state in your application, and React will efficiently update and render just the right components when your data changes. Declarative views make your code more predictable, simpler to understand, and easier to debug.
  • Component-Based: Build encapsulated components that manage their own state, then compose them to make complex UIs. Since component logic is written in JavaScript instead of templates, you can easily pass rich data through your app and keep state out of the DOM.
  • Learn Once, Write Anywhere: We don't make assumptions about the rest of your technology stack, so you can develop new features in React without rewriting existing code. React can also render on the server using Node and power mobile apps using React Native.


React has been designed for gradual adoption from the start, and you can use as little or as much React as you need:

You can use React as a <script> tag from a CDN, or as a react package on npm.

To use

There are several simple server implementations included. They all serve static files from public/ and handle requests to /api/comments to fetch or add data. Start a server with one of the following:


npm install
node server.js
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pip install -r requirements.txt
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ruby server.rb
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php server.php
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go run server.go
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cpan Mojolicious
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And visit http://localhost:3000/. Try opening multiple tabs!

Changing the port

You can change the port number by setting the $PORT environment variable before invoking any of the scripts above, e.g.,

PORT=3001 node server.js
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We have several examples on the website. Here is the first one to get you started:

function HelloMessage({ name }) {
  return <div>Hello {name}</div>;

  <HelloMessage name="Taylor" />,
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This example will render "Hello Taylor" into a container on the page.

You'll notice that we used an HTML-like syntax; we call it JSX. JSX is not required to use React, but it makes code more readable, and writing it feels like writing HTML. If you're using React as a <script> tag, read this section on integrating JSX; otherwise, the recommended JavaScript toolchains handle it automatically.


The main purpose of this repository is to continue evolving React core, making it faster and easier to use. Development of React happens in the open on GitHub, and we are grateful to the community for contributing bugfixes and improvements. Read below to learn how you can take part in improving React.

Code of Conduct

Facebook has adopted a Code of Conduct that we expect project participants to adhere to. Please read the full text so that you can understand what actions will and will not be tolerated.

Contributing Guide

Read our contributing guide to learn about our development process, how to propose bugfixes and improvements, and how to build and test your changes to React.

Good First Issues

To help you get your feet wet and get you familiar with our contribution process, we have a list of good first issues that contain bugs which have a relatively limited scope. This is a great place to get started.

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