Detailed explanation of how to quickly query Node.js version information (six methods)

Node.js is a fast, lightweight JavaScript runtime based on the Chrome V8 engine. As applications become larger and larger, Node.js versions are updated more frequently. This article is designed to help developers quickly query Node.js version information.

1. Use the node command to query version information

The node command provides a parameter -v, which can output Node.js version information in the console. Enter the following command in the terminal to query the Node.js version:

$ node -v

The query result is similar to:

v14.16.0

2. Use the process object to query version information

The process object is A built-in object of Node.js that can be used to obtain the currently running Node.js version. Add the following code to the JavaScript file to query the version information:

console.log(process.version);

The output result is:

v14.16.0

3. Use npm to query the Node.js version information

npm is Node .js package manager, you can query Node.js version information through the npm command. Enter the following command in the terminal to query the Node.js version information:

$ npm version node

The running result is:

v14.16.0

4. Use nvm to query the Node.js version information

nvm (Node Version Manager) is a Node.js version management tool that can easily manage multiple Node.js versions. Enter the following command in the terminal to query the Node.js version currently being used:

$ nvm current

The output result is:

v14.16.0

Use the following command to list all Node installed in the current system .js version:

$ nvm ls

The running result is:

->       v14.16.0
         v10.19.0
         v12.18.3
default -> node (-> v14.16.0)

5. Use package.json to query the Node.js version information

In the root directory of the Node.js application , there is a file named package.json, which records the dependencies and version information of the application. We can view the Node.js version information that the current application depends on in this file.

Open the package.json file and you can see the following content:

{
  "name": "nodejs-demo",
  "version": "1.0.0",
  "dependencies": {
    "express": "^4.17.1"
  },
  "devDependencies": {},
  "scripts": {
    "start": "node index.js"
  },
  "engines": {
    "node": ">=14.0.0"
  }
}

In the engines field, you can see the Node.js version range that the current application depends on.

6. Use HTTP API to query Node.js version information

Node.js provides some basic HTTP modules, and you can implement the HTTP API to obtain Node.js version information by writing JavaScript scripts. The following is the code that uses HTTP API to query Node.js version information:

const http = require('http');

const server = http.createServer((request, response) => {
  response.writeHead(200, { 'Content-Type': 'text/plain' });
  response.end(process.version);
});

const PORT = 8080;
server.listen(PORT, () => {
  console.log(`Server running at http://localhost:${PORT}/`);
});

This code creates an HTTP server. When there is a request to access the URL with port 8080, it will return the currently running Node.js version information. .

7. Summary

This article introduces a variety of methods for querying Node.js version information. Developers can choose the method that suits them according to their own needs. During the development process, it is also important to understand the currently used Node.js version information to avoid some errors and problems caused by version incompatibility and other reasons.

The above is the detailed content of Detailed explanation of how to quickly query Node.js version information (six methods). For more information, please follow other related articles on the PHP Chinese website!