Home Web Front-end Front-end Q&A What is the top-level object of node

What is the top-level object of node

Mar 22, 2022 pm 06:17 PM
node

The top-level object of node is the global object. The global object is the global object of node. This object and all its properties can be accessed anywhere in the program; the most fundamental role of the global object is to serve as the host of global variables.

What is the top-level object of node

The operating environment of this tutorial: windows7 system, nodejs version 12.19.0, DELL G3 computer.

The top-level object refers to the window in the browser and the global object in the node environment.

There is a special object in JavaScript called the global object (Global Object). It and all its properties can be accessed anywhere in the program, that is, global variables.

In browser JavaScript, usually window is the global object, and the global object in Node.js is global. All global variables (except global itself) are properties of the global object.

In Node.js we can directly access global properties without including it in the application.

Global objects and global variables

The most fundamental role of global is to serve as the host of global variables. According to the definition of ECMAScript, variables that meet the following conditions are global variables:

  • Variables defined in the outermost layer;

  • Properties of global objects ;

  • Implicitly defined variables (variables that are not directly assigned a value).

When you define a global variable, the variable also becomes a property of the global object, and vice versa. It should be noted that in Node.js you cannot define variables at the outermost level, because all user code belongs to the current module, and the module itself is not the outermost context.

Note: It is best not to use var to define variables to avoid introducing global variables, because global variables will pollute the namespace and increase the risk of code coupling.

The __filename attribute and __dirname attribute of the global object

__filenameAttribute: Returns the file of the currently executed file Path, the path is the absolute path after parsing. In the module, the path is the path of the module file. This attribute is not a global attribute, but the

__dirname attribute of the module: Return The path to the directory where the currently executing script file is located. This attribute is also for the module, rather than other common objects under the global

What is the top-level object of node

global object. There are many other common objects. Please refer to the API. (http://nodejs.cn/api/globals.html)

What is the top-level object of node

What is the top-level object of node

For more node-related knowledge, please visit: nodejs tutorial!

The above is the detailed content of What is the top-level object of node. For more information, please follow other related articles on the PHP Chinese website!

Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

How to delete node in nvm How to delete node in nvm Dec 29, 2022 am 10:07 AM

How to delete node with nvm: 1. Download "nvm-setup.zip" and install it on the C drive; 2. Configure environment variables and check the version number through the "nvm -v" command; 3. Use the "nvm install" command Install node; 4. Delete the installed node through the "nvm uninstall" command.

How to use express to handle file upload in node project How to use express to handle file upload in node project Mar 28, 2023 pm 07:28 PM

How to handle file upload? The following article will introduce to you how to use express to handle file uploads in the node project. I hope it will be helpful to you!

How to do Docker mirroring of Node service? Detailed explanation of extreme optimization How to do Docker mirroring of Node service? Detailed explanation of extreme optimization Oct 19, 2022 pm 07:38 PM

During this period, I was developing a HTML dynamic service that is common to all categories of Tencent documents. In order to facilitate the generation and deployment of access to various categories, and to follow the trend of cloud migration, I considered using Docker to fix service content and manage product versions in a unified manner. . This article will share the optimization experience I accumulated in the process of serving Docker for your reference.

An in-depth analysis of Node's process management tool 'pm2” An in-depth analysis of Node's process management tool 'pm2” Apr 03, 2023 pm 06:02 PM

This article will share with you Node's process management tool "pm2", and talk about why pm2 is needed, how to install and use pm2, I hope it will be helpful to everyone!

Pi Node Teaching: What is a Pi Node? How to install and set up Pi Node? Pi Node Teaching: What is a Pi Node? How to install and set up Pi Node? Mar 05, 2025 pm 05:57 PM

Detailed explanation and installation guide for PiNetwork nodes This article will introduce the PiNetwork ecosystem in detail - Pi nodes, a key role in the PiNetwork ecosystem, and provide complete steps for installation and configuration. After the launch of the PiNetwork blockchain test network, Pi nodes have become an important part of many pioneers actively participating in the testing, preparing for the upcoming main network release. If you don’t know PiNetwork yet, please refer to what is Picoin? What is the price for listing? Pi usage, mining and security analysis. What is PiNetwork? The PiNetwork project started in 2019 and owns its exclusive cryptocurrency Pi Coin. The project aims to create a one that everyone can participate

What to do if npm node gyp fails What to do if npm node gyp fails Dec 29, 2022 pm 02:42 PM

npm node gyp fails because "node-gyp.js" does not match the version of "Node.js". The solution is: 1. Clear the node cache through "npm cache clean -f"; 2. Through "npm install -g n" Install the n module; 3. Install the "node v12.21.0" version through the "n v12.21.0" command.

Let's talk about how to use pkg to package Node.js projects into executable files. Let's talk about how to use pkg to package Node.js projects into executable files. Dec 02, 2022 pm 09:06 PM

How to package nodejs executable file with pkg? The following article will introduce to you how to use pkg to package a Node project into an executable file. I hope it will be helpful to you!

Token-based authentication with Angular and Node Token-based authentication with Angular and Node Sep 01, 2023 pm 02:01 PM

Authentication is one of the most important parts of any web application. This tutorial discusses token-based authentication systems and how they differ from traditional login systems. By the end of this tutorial, you will see a fully working demo written in Angular and Node.js. Traditional Authentication Systems Before moving on to token-based authentication systems, let’s take a look at traditional authentication systems. The user provides their username and password in the login form and clicks Login. After making the request, authenticate the user on the backend by querying the database. If the request is valid, a session is created using the user information obtained from the database, and the session information is returned in the response header so that the session ID is stored in the browser. Provides access to applications subject to

See all articles