How nodejs runs

Node.js is a JavaScript running environment based on the Chrome V8 engine. It can be used to run JavaScript on the server side. It provides many functions and APIs, including file system operations, network communication, module loading, etc. So, how does Node.js work?

Node.js requires the following steps to run:

1. Install Node.js

First, Node.js needs to be installed locally. The official website provides installation packages for various platforms, which can be downloaded and installed according to your own operating system. After the installation is complete, enter the node -v command in the command line window. If the current Node.js version number can be output, the installation is successful.

2. Create project

Select a directory on the local disk as the project directory, create a JavaScript file in the directory and name it app.js.

3. Write code

Write the code that needs to be run in the app.js file. For example, the following code will output "Hello, World!" to the console:

console.log("Hello, World!");

4. Run the code

Open the command line window, enter the project directory, and use node app.js Command to run code. This starts the Node.js process and runs the code in the app.js file. If everything goes well, the console will print "Hello, World!".

5. Using modules

Node.js has many commonly used modules built-in, which can be introduced and used through the require function. For example, we can use the http module to create a simple Web server:

const http = require("http");

const server = http.createServer((request, response) => {
  response.end("Hello, World!");
});

server.listen(3000, () => {
  console.log("Server running at http://localhost:3000/");
});

The above code creates an HTTP server, listens to port 3000, and returns "Hello, World" when the client accesses it. !". Enter node app.js in the command line window to start the server.

Summary

The above is the basic process of running Node.js. You can use JavaScript in your backend environment by installing Node.js, writing code in your local project directory, and running the code using a command line window. Node.js also provides a wealth of modules and libraries, allowing developers to easily develop efficient and stable back-end applications.

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