gowthm

function debounce(fn, timer) {
    let timeout;
    return function(...arguments) {
        clearTimeout(timeout);
        timeout = setTimeout(() => {
            fn.apply(this, arguments)
            
        }, timer)
    }
}

gowthm

// Singleton pattern
// SINGLEton. We use this design pattern when we only want a single instance of a class. 
// That means we cannot create multiple instances - just one. If there is no instance, a new one is created.
// If there is an existing instance, it will use that one.

class Database {
constructor() {
    this.connection = null;
}
    static getDatabase() {

gowthm

let a ={}
let b = {key: 'b'}
let c = {key: 'c'}

a[b] = 78
a[c] = 34
console.log(a[b])


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gowthm

process.nextTick(() => console.log(1));
Promise.resolve().then(() => console.log(2));
Promise.resolve().then(() => {
    console.log(3);
    process.nextTick(() => console.log(4));
    Promise.resolve().then(() => console.log(5));
}).then(() => {
    console.log(6);
})

gowthm

// Promise.all
//will reject with this first rejection message

const p1 = new Promise((resolve, reject) => {
  setTimeout(() => {
    resolve("From Prmose1")
  }, 1000)
})
const p2 = "From Promise2"

gowthm

let s = 'aaabbcddddswwaaaaa';
let c = 1;
let data = []
for (let i=0; i<s.length; i++) {
  if (s[i] != s[i+1]) {
      data.push(c);
      data.push(s[i]);
      c = 1;
  } else {
    c = c + 1;

gowthm

let a = 10;

let func = function (){
    let b = 20;
    console.log("a and b is accessible (outer):", a, b);
    let innerFunc= function (){
        var c = 30;
        console.log("a and b and c is accessible (innner):", a, b, c);
        let innerFunc1 = function() {
          console.log('Parent variable can accessible')

gowthm

// Regular Function with "this"

function Car() {
  this.speed = 0;
  this.speedUp = function(speed) {
    this.speed = speed;
  //  let self = this;              ----> without line anonymous function take as shadow from speedUp function.
    setTimeout(function () {
      console.log(self.speed)
    }, 100)

gowthm

const fs = require('fs');
const express = require('express');
const bodyParser = require('body-parser');
const path = require('path');
const app = express();
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({extended: true}))
app.post('/upload-file', async function(req, res) {
    const fileName = req.body.fileName;
    const base64 = req.body.base64Data;