https://github.com/satyamgupta53/java-script-essentials
Comprehensive JavaScript repository 🌟 covering fundamentals and DOM manipulation 🛠️, advanced concepts like asynchronous programming ⏳, closures 🎯, and dynamic imports 📦 for seamless development 🚀
https://github.com/satyamgupta53/java-script-essentials
dom-manipulation javascript nodejs v8-javascript-engine
Last synced: 8 months ago
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Comprehensive JavaScript repository 🌟 covering fundamentals and DOM manipulation 🛠️, advanced concepts like asynchronous programming ⏳, closures 🎯, and dynamic imports 📦 for seamless development 🚀
- Host: GitHub
- URL: https://github.com/satyamgupta53/java-script-essentials
- Owner: satyamgupta53
- Created: 2025-03-30T04:13:17.000Z (9 months ago)
- Default Branch: main
- Last Pushed: 2025-04-02T15:04:31.000Z (9 months ago)
- Last Synced: 2025-04-02T15:24:57.174Z (9 months ago)
- Topics: dom-manipulation, javascript, nodejs, v8-javascript-engine
- Language: JavaScript
- Homepage:
- Size: 51.8 KB
- Stars: 1
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
## Introduction
Node JS is runtime environment to execute codes on server, based on v8 engine (by google, C++ based) uses JIT compilation, executing codes faster. **Parsing** — creating abstract syntax tree AST, **Interpretation** — Ignition interpreter (keeping hot code, for optimization) to byte codes, **Optimization** — hot code to Turbo Fan compiler (uses inline caching, copy elision), converting into machine code, **De-Optimization** — when assumptions fail, discarding optimized code, Ignition re-interprets and then, compilation. **Garbage Collection** — uses mark-sweep algorithms to mark live variables & objects, sweeps unused ones.
```jsx
console.log("Hello World !");
process.stdout.write("Another way to print");
console.table({city: ["jaipur", "delhi"], state: ["rajasthan", "delhi"]});
typeof(balance) --> return number (method to find data type)
console.log(`Hello! My name is ${username}`); // string interpolation
```
**Datatypes** — `string, number, boolean, bigint, undefined, null, Object`. **Logical operations** — `&& (and), || (or), !)`. Back ticks allows to use variables in string.
## Backend with Java Script
### Node JS & Express JS
`Ngnix` is HTTP web server, we connect this to our `src/` directory, where we have our static web-pages & backend logic. Also, much of the Node JS is built with asynchronous event-driven architecture with objects like `emitters`.
```jsx
/* Writing your own server in pure Node JS */
server = http.createServer((req, res) => {
fs.readFile(path.join(__dirname, req.url === '/' ? 'index.html' : `${req.url}`),
(err, content) => {
if(!err) {
res.writeHead(200, {"content-type": "text/html"});
res.end(content, "utf-8");
}
})
});
server.listen(port=3000, () => {
console.log("Server is successfully running on port 3000");
});
/* Creating logging functionality */
class Logger extends EventEmitter {
log(message) {'message': {messsage}};
}
setInterval(() => {
const memoryUsage = (os.freemem() / os.totalmem()) * 100;
logger.log(`Current memory usage: ${memoryUsage.toFixed(2)}`);
}, 3000);
logger.on("message", logToFile);
const logToFile = (event) => {
const logMessage = `${new Date().toDateString()} - ${event.message} \n`;
console.log(logMessage);
fs.appendFile(logFile, logMessage, (err) => {
if (err) console.error("Error writing to the file: ", err);
});
};
```
### **Database SQL vs NO-SQL**
They are required to store data persistently, major types includes SQL DB and NO-SQL DB (not-only SQL). We need Object-Relational Mapper ORM like `mongoose` to communicate with Mongo DB. SQL refers to Structured Query Language.