How to install and download files in nodejs

With the development of Internet technology, more and more developers are beginning to use Node.js for development. Node.js is a JavaScript running environment based on the Chrome V8 engine. It can run JavaScript on the server side and is efficient, lightweight and scalable. Before using Node.js, you first need to download the Node.js installation package from the official website and install it.

1. Node.js official website download

The Node.js official website provides installation packages for different systems such as Windows, macOS, and Linux. The download URL is: https://nodejs.org/en/download/.

2. Download and install Node.js and configure environment variables

1. Windows system installation

a. On the Node.js official website download page, select Download the Windows Installer version and double-click to run it after the download is complete.

b. In the pop-up installation wizard, follow the prompts to install. Note that selecting the "Add to PATH" option will automatically configure the environment variables.

c. After the installation is completed, open the cmd command line and enter node -v. If the Node.js version can be displayed normally, it means the installation has been successful.

2. macOS system installation

a. On the Node.js official website download page, select the macOS Installer version to download. After the download is complete, double-click to run.

b. In the pop-up installation wizard, follow the prompts to install. After the installation is complete, enter node -v in the terminal. If the Node.js version can be displayed normally, it means the installation has been successful.

3. Linux system installation

a. On the Node.js official website download page, select the Linux version to download.

b. Unzip the downloaded installation package. The command is as follows:

tar -xvf node-v8.0.0-linux-x64.tar.gz

c. Move the decompressed folder to the /opt directory. The command is as follows:

sudo mv node-v8.0.0-linux-x64 /opt/

d. Configure environment variables and add the executable file path of Node.js to PATH. The command is as follows:

export PATH=$PATH:/opt/node-v8.0.0-linux-x64/bin

e. Enter node -v in the terminal, if Node can be displayed normally .js version, indicating that it has been installed successfully.

3. Use Node.js

After installing Node.js, you can run JavaScript code on the command line. Enter the node command on the command line to enter the REPL (Read-Eval-Print Loop) environment.

1. Hello World

Enter the following code:

console.log('Hello World');

After pressing enter, Hello World will be output.

2. Create http server

Enter the following code:

var http = require('http');
http.createServer(function ( req, res) {
res.writeHead(200, {'Content-Type': 'text/plain'});
res.end('Hello World\n');
}). listen(8080, '127.0.0.1');
console.log('Server running at http://127.0.0.1:8080/');

Enter in the browser http://127.0.0.1:8080/ will output Hello World. This example demonstrates how to create a simple http server.

4. Summary

Node.js has become one of the mainstream technologies in modern web application development. Node.js is easy to install, just download the installation package from the official website. Once installed, you can use Node.js from the command line to run JavaScript code and perform server-side development. For ease of use, it is recommended to select the "Add to PATH" option when installing Node.js to automatically configure environment variables.

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