How to modify nodejs port number

In recent years, with the continuous development of front-end technology, Node.js has become a very popular back-end platform. Developers choose to use Node.js to develop web applications mainly because of its high performance, scalability and ease of learning. During the development process, it is sometimes necessary to modify the port number of Node.js to ensure that the Node.js service can run on its own host. This article will introduce how to modify the Node.js port number.

In the default settings of Node.js, it will default to the listening port number of 3000. If you want to use other port numbers, such as 8080 or 5000, or higher numeric port numbers, you can do so by modifying the code or setting environment variables.

1. Modify the port number by modifying the code

To modify the port number by modifying the code file, you need to find a file named "app.js" or "server.js" (or other JavaScript files that you use to write Node.js programs). In the file, you can find statements similar to the following code:

const server = app.listen(3000, () => {
  console.log(`App running on port 3000`);
});

In this example, the Node.js service is listening on port 3000. To change it to another port, you just need to modify the above code as follows:

const server = app.listen(8080, () => {
  console.log(`App running on port 8080`);
});

After modifying the above code, you just need to save and restart the Node.js service, and you can use the new port number to run your application.

2. Modify the port number by setting environment variables

In a production environment, you may need to run multiple Node.js applications on different servers. If you decide to use a different port number to run each application, then using environment variables may be a better option. You can set environment variables by using PROCESS.ENV.PORT. For example:

const port = process.env.PORT || 3000;
const server = app.listen(port, () => {
  console.log(`App running on port ${port}`);
});

In this code file, Node.js will use the value of PROCESS.ENV.PORT as the port number. If not set, it will use the default port number 3000 to run the application. This approach ensures that your Node.js application can run on multiple servers without requiring changes to code files or configuration files.

Summary

In Node.js application development, changing the port number is a very common requirement. When you need to run your application on different servers, you can use environment variables to set different port numbers. And if you only need to run the application on a single server, you can modify the port number by modifying the code file.

No matter which method you use, be sure to restart your Node.js application after modifying the port number to ensure that the modified port number can take effect. Hope this article can help you better understand how to modify the Node.js port number.

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