Detailed explanation of several methods of querying Node.js modules

In Node.js, a module is the organizational unit of code. Node.js provides a wealth of built-in modules, and also allows us to write and import modules ourselves. When we need to use a module, we need to query and understand information about the module in order to use it correctly.

This article will introduce several methods of querying Node.js modules to help you better understand and use modules.

1. Query built-in modules

In the standard library of Node.js, there are many built-in modules for us to use. To query information about built-in modules, you can use the documentation website api documentation provided by Node.js. In this website you can find and learn all about specific modules and their APIs (Application Programming Interfaces). The following are the steps to query the built-in modules:

1. Open the website http://nodejs.cn/api/.

2. Search for the module you want

3. Click to view the module details

For example, we want to know about the fs (file system) module of Node.js For information, you can open the Node.js documentation website, search for the fs module, and then click on the module. Then we will see a page with all the information about the module, such as the module's description, API list, etc.

2. Query third-party modules

In the Node.js community, there are thousands of third-party modules for us to use. To query information about third-party modules, you can view it on the npm website. npm is the Node.js package manager and is an open source registry that contains many Node.js modules. The following are the steps to query third-party modules:

1. Open the website https://www.npmjs.com/.

2. Search for the module you want

3. Click to view the module details

For example, if we want to know information about the express framework of Node.js, we can open On the npm website, search for the express module and click on the module. We will then see a page with all the information about the module, such as its description, version number, download count, and more.

3. Query installed modules

In Node.js, we can use npm to install and uninstall third-party modules. To query information about installed modules, you can use the npm list command. Here are the steps to query installed modules:

1. Open a terminal or command prompt.

2. Enter the npm list command.

3. View the output list, which contains information such as all installed modules and their version numbers.

For example, if we want to view information about all installed modules in the current project, we can open a terminal or command prompt, enter the project directory, and then enter the npm list command. Then we will see information about all modules installed in the project, including their names, version numbers, etc.

4. Query the documentation in the module

Some modules provide detailed documentation, which can help developers better understand and use the module. To query the documentation in a module, you can view the module's README file and code comments. The following are the steps to query the documents in the module:

1. Open the project directory where the module is located.

2. Find and open the README file.

3. View the comments in the code.

For example, if we want to know information about the request module of Node.js, we can open the project directory where the module is located, and open the README file and code file. Then we will see the documentation and related comments of the module to help us better understand and use the module.

In short, when we need to use a module, it is very important to query the module. Through the above methods, we can understand the information of any module and use them better.

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