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Questions tagged [node.js]

Node.js is an event-based, non-blocking, asynchronous I/O runtime that uses Google's V8 JavaScript engine and libuv library. It is used for developing applications that make heavy use of the ability to run JavaScript both on the client as well as on the server side and therefore benefit from the re-usability of code and the lack of context switching.

Node.js is an event-based, non-blocking, asynchronous I/O (input/output) runtime that uses Google's V8 JavaScript Engine.

, commonly just called Node, is often used for developing applications that rely on the ability to run both on the client and server side. Running the same language on both the client and the server benefits from improved code reusability and less context switching.

A notable feature of is that it is non-blocking – if one task stalls or pauses for an I/O operation, another can take over while idle. This allows for high efficiency as the program as a whole never has to idle and wait for one task to finish. Libraries such as async take advantage of this capability. More information can be found here.

It's also possible to use mature JavaScript frameworks like YUI and jQuery for server-side DOM manipulation in .

To ease the development of complex JavaScript further, Node.js supports the CommonJS standard that allows for modularized development and the distribution of software in packages via the Node Package Manager (NPM).

Download node.js:

Applications that can be written using Node.js include, but are not limited to:

  • Static file servers
  • Web Application frameworks
  • Messaging middleware
  • Servers for HTML5 multi player games, or streaming audio/video
  • Real time applications
  • Cross-platform programs

When asking questions about Node.js, you should:

  1. Make sure to check the official API documentation before asking, your question might be trivial.
  2. Isolate the problem and reproduce it with as little code as possible.
  3. If the question has nothing to do with anything that's specific, please consider asking it as a question instead.
  4. Mention which version of Node.js you are running. When in doubt, use node -v or node --version.
  5. Make sure to only use the tag, since is ambiguous.

Interesting Questions and Answers

Useful Links

Tutorials, Guides and Books

Talks, Presentations, and Podcasts on Node.js

Free Node.js Books and Resources

Chat Room & Mailing list

Logging

  • pino - Extremely fast logger inspired by Bunyan.
  • winston - Multi-transport async logging library.
  • console-log-level - The most simple logger imaginable with support for - log levels and custom prefixes.
  • storyboard - End-to-end, hierarchical, real-time, colorful logs and stories.
  • signale - Hackable console logger with beautiful output.

Official logo

Official logo

Node.js is copyrighted by the openJS Foundation

466830 questions
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Why does "npm install" rewrite package-lock.json?

I just recently upgraded to npm@5. I now have a package-lock.json file with everything from package.json. I would expect that, when I run npm install that the dependency versions would be pulled from the lock file to determine what should be…
Viper Bailey
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Error "npm WARN package.json: No repository field"

I installed Express.js with the following command: sudo npm install -g express I get the following warnings: npm WARN package.json range-parser@0.0.4 No repository field. npm WARN package.json fresh@0.1.0 No repository field. npm WARN package.json…
JR Galia
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How to access POST form fields in Express

Here is my simple form:
murvinlai
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Node.js: printing to console without a trailing newline?

Is there a method for printing to the console without a trailing newline? The console object documentation doesn't say anything regarding that: console.log() Prints to stdout with newline. This function can take multiple arguments in a…
Evan Carroll
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Is there a way to get version from package.json in nodejs code?

Is there a way to get the version set in package.json in a nodejs app? I would want something like this var port = process.env.PORT || 3000 app.listen port console.log "Express server listening on port %d in %s mode %s", app.address().port,…
Abhik Bose Pramanik
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How can I run multiple npm scripts in parallel?

In my package.json I have these two scripts: "scripts": { "start-watch": "nodemon run-babel index.js", "wp-server": "webpack-dev-server", } I have to run these 2 scripts in parallel everytime I start developing in Node.js. The first…
Andre Pena
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How to fix "ReferenceError: primordials is not defined" in Node.js

I have installed Node.js modules by 'npm install', and then I tried to do gulp sass-watch in a command prompt. After that, I got the below response. [18:18:32] Requiring external module babel-register fs.js:27 const { Math, Object, Reflect } =…
Ramesh
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What is "export default" in JavaScript?

File: SafeString.js // Build out our basic SafeString type function SafeString(string) { this.string = string; } SafeString.prototype.toString = function() { return "" + this.string; }; export default SafeString; I have never seen export…
damphat
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How can I print a circular structure in a JSON-like format?

I have a big object I want to convert to JSON and send. However it has circular structure, so if I try to use JSON.stringify() I'll get: TypeError: Converting circular structure to JSON or TypeError: cyclic object value I want to toss whatever…
Harry
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How do I convert an existing callback API to promises?

I want to work with promises but I have a callback API in a format like: 1. DOM load or other one time event: window.onload; // set to callback ... window.onload = function() { }; 2. Plain callback: function request(onChangeHandler) { …
Benjamin Gruenbaum
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module.exports vs exports in Node.js

I've found the following contract in a Node.js module: module.exports = exports = nano = function database_module(cfg) {...} I wonder what's the difference between module.exports and exports and why both are used here.
Andreas Köberle
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How do you prevent install of "devDependencies" NPM modules for Node.js (package.json)?

I have this in my package.json file (shortened version): { "name": "a-module", "version": "0.0.1", "dependencies": { "coffee-script": ">= 1.1.3" }, "devDependencies": { "stylus": ">= 0.17.0" } } I am using NPM…
Lance
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Call async/await functions in parallel

As far as I understand, in ES7/ES2016 putting multiple await's in code will work similar to chaining .then() with promises, meaning that they will execute one after the other rather than in parallel. So, for example, we have this code: await…
Victor Marchuk
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Node.js quick file server (static files over HTTP)

Is there Node.js ready-to-use tool (installed with npm), that would help me expose folder content as file server over HTTP. Example, if I have D:\Folder\file.zip D:\Folder\file2.html D:\Folder\folder\file-in-folder.jpg Then starting in D:\Folder\…
Paul Verest
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Using Node.JS, how do I read a JSON file into (server) memory?

Background I am doing some experimentation with Node.js and would like to read a JSON object, either from a text file or a .js file (which is better??) into memory so that I can access that object quickly from code. I realize that there are things…
Matt Cashatt
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