Node runs in a single thread, using a single-threaded asynchronous non-blocking mode; but strictly speaking, there are multiple threads in the node. Single-thread means that there is only one js engine in the node running on the main thread, and the others Asynchronous operations are also executed by independent threads. At the same time, node is single-threaded by default, and a "node.js" cannot utilize multi-core resources.

The operating environment of this tutorial: windows10 system, nodejs version 12.19.0, Dell G3 computer.
Are all nodes run in a single thread?
Node is run in a single thread, using single-thread asynchronous non-blocking mode.
When it comes to node, we can immediately think of words such as single-threaded, asynchronous IO, and event-driven. The first thing to clarify is whether node is really single-threaded. If it is single-threaded, then where are asynchronous IO and scheduled events (setTimeout, setInterval, etc.) executed.
Actually, strictly speaking, node is not single-threaded. There are many kinds of threads in node, including:
js engine execution thread
Timer thread (setTimeout, setInterval)
Asynchronous http thread (ajax)
What we usually call single thread means that there is only one js engine in node running on the main thread. Other asynchronous IO and event-driven related threads use libuv to implement internal thread pools and thread scheduling. There is an Event Loop in libv, and switching through Event Loop can achieve an effect similar to multi-threading. Simply put, Event Loop maintains an execution stack and an event queue. If asynchronous IO and timer functions are found in the current execution stack, these asynchronous callback functions will be put into the event queue. After the execution of the current execution stack is completed, the asynchronous callback functions in the event queue are executed in a certain order from the event queue.

In the above figure, from the execution stack to the event queue, and finally the callback function is executed in a certain order in the event queue, the whole process is a simplified version of Event Loop. In addition, when the callback function is executed, an execution stack will also be generated. Asynchronous functions may be nested inside the callback function, which means that the execution stack is nested.
In other words, the single thread in node means that the js engine only runs on the only main thread. Other asynchronous operations also have independent threads to execute. Through libv's Event Loop, a similar multi-thread is implemented. Thread context switching and thread pool scheduling. Threads are the smallest processes, so node is also a single process. This explains why node is single-threaded and single-process.
Recommended learning: "nodejs video tutorial"
The above is the detailed content of Does node all run single-threaded?. For more information, please follow other related articles on the PHP Chinese website!
React: Creating Dynamic and Interactive User InterfacesApr 14, 2025 am 12:08 AMReact is the tool of choice for building dynamic and interactive user interfaces. 1) Componentization and JSX make UI splitting and reusing simple. 2) State management is implemented through the useState hook to trigger UI updates. 3) The event processing mechanism responds to user interaction and improves user experience.
React vs. Backend Frameworks: A ComparisonApr 13, 2025 am 12:06 AMReact is a front-end framework for building user interfaces; a back-end framework is used to build server-side applications. React provides componentized and efficient UI updates, and the backend framework provides a complete backend service solution. When choosing a technology stack, project requirements, team skills, and scalability should be considered.
HTML and React: The Relationship Between Markup and ComponentsApr 12, 2025 am 12:03 AMThe relationship between HTML and React is the core of front-end development, and they jointly build the user interface of modern web applications. 1) HTML defines the content structure and semantics, and React builds a dynamic interface through componentization. 2) React components use JSX syntax to embed HTML to achieve intelligent rendering. 3) Component life cycle manages HTML rendering and updates dynamically according to state and attributes. 4) Use components to optimize HTML structure and improve maintainability. 5) Performance optimization includes avoiding unnecessary rendering, using key attributes, and keeping the component single responsibility.
React and the Frontend: Building Interactive ExperiencesApr 11, 2025 am 12:02 AMReact is the preferred tool for building interactive front-end experiences. 1) React simplifies UI development through componentization and virtual DOM. 2) Components are divided into function components and class components. Function components are simpler and class components provide more life cycle methods. 3) The working principle of React relies on virtual DOM and reconciliation algorithm to improve performance. 4) State management uses useState or this.state, and life cycle methods such as componentDidMount are used for specific logic. 5) Basic usage includes creating components and managing state, and advanced usage involves custom hooks and performance optimization. 6) Common errors include improper status updates and performance issues, debugging skills include using ReactDevTools and Excellent
React and the Frontend Stack: The Tools and TechnologiesApr 10, 2025 am 09:34 AMReact is a JavaScript library for building user interfaces, with its core components and state management. 1) Simplify UI development through componentization and state management. 2) The working principle includes reconciliation and rendering, and optimization can be implemented through React.memo and useMemo. 3) The basic usage is to create and render components, and the advanced usage includes using Hooks and ContextAPI. 4) Common errors such as improper status update, you can use ReactDevTools to debug. 5) Performance optimization includes using React.memo, virtualization lists and CodeSplitting, and keeping code readable and maintainable is best practice.
React's Role in HTML: Enhancing User ExperienceApr 09, 2025 am 12:11 AMReact combines JSX and HTML to improve user experience. 1) JSX embeds HTML to make development more intuitive. 2) The virtual DOM mechanism optimizes performance and reduces DOM operations. 3) Component-based management UI to improve maintainability. 4) State management and event processing enhance interactivity.
React Components: Creating Reusable Elements in HTMLApr 08, 2025 pm 05:53 PMReact components can be defined by functions or classes, encapsulating UI logic and accepting input data through props. 1) Define components: Use functions or classes to return React elements. 2) Rendering component: React calls render method or executes function component. 3) Multiplexing components: pass data through props to build a complex UI. The lifecycle approach of components allows logic to be executed at different stages, improving development efficiency and code maintainability.
React Strict Mode PurposeApr 02, 2025 pm 05:51 PMReact Strict Mode is a development tool that highlights potential issues in React applications by activating additional checks and warnings. It helps identify legacy code, unsafe lifecycles, and side effects, encouraging modern React practices.


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

AI Hentai Generator
Generate AI Hentai for free.

Hot Article

Hot Tools

Atom editor mac version download
The most popular open source editor

ZendStudio 13.5.1 Mac
Powerful PHP integrated development environment

Safe Exam Browser
Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.

EditPlus Chinese cracked version
Small size, syntax highlighting, does not support code prompt function

Dreamweaver CS6
Visual web development tools







