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Introduction

What​

Node.js is an asynchronous event driven JavaScript runtime, Node is designed to build scalable network applications.

Commonly known as server-side JavaScript (in fact, the execution of JavaScript on the server is done with a virtual machine (V8/Chakra), Node is like a coordinator, a wrapper).

But it is used more than that, it has:

  • many built-in modules (fs, http, crypto, zip, ...)
  • provides asynchronous APIs (without needing to deal with threads) →\rightarrow biggest benefit
  • C++ addons

Why​

  • APIs and microservices

    More "lightweight" alternative for application server style deployment model: there's no server to deploy your code to, your code is the server →\rightarrow easier to build increasingly complex application.

    const http = require('http');

    const hostname = '127.0.0.1';
    const port = 3000;

    const server = http.createServer((req, res) => {
      res.statusCode = 200;
      res.setHeader('Content-Type', 'text/plain');
      res.end('Hello World');
    });

    server.listen(port, hostname, () => {
      console.log(`Server running at http://${hostname}:${port}/`);
    });

  • Serverless cloud functions

    As a dynamic language runtime with a fast startup & low memory consumption.

  • Command line applications

    webpack, gulp, ESLint, Yeoman, etc. written in JavaScript and run in Node.js.

  • Desktop applications

    Due to Electron framework. For e.g. Skype, Github Desktop, Visual Studio Code, Slack, Atom, Hyper, etc.

How​

History​

Node Clusters​

Read more about we should let a Node process to crash and exit.

Like its name, Node is actually nodes. In production, server runs cluster of node processes. With many-cores CPU, each node process is running for each core. One working process exiting should not mean the system is down.

There will be cluster have a master process, which should be monitoring worker processes. And it starts the new one when the process crashes and exits.

There are tools like PM2 that wrap the cluster module to run your Node application in production.

Why Not To​

  • CPU-intensive tasks

    Node is designed to build scalable network app, "network" implies "I/O" →\rightarrow required heavy use of CPU, better for I/O-intensive use cases

  • Dynamic typed nature of JavaScript

ResRef​

*** ResRef implies Resources & References :D ***

https://jscomplete.com/learn/why-node-for-react

https://www.freecodecamp.org/news/hard-coding-concepts-explained-with-simple-real-life-analogies-280635e98e37/