Harshmakadia

// 1. Go to https://analytics.twitter.com/ 

// 2. Keep scrolling till the end until all the stats data is loaded

// 3. Right click on the page click on last option "Inspect" a window should open select console from that

// 4. copy this entire function

function getVal (val) {
    val=val.replace(/\,/g,'');

Harshmakadia

import React from "react";

function Form() {
  const [state, setState] = React.useState({
    firstName: "",
    lastName: ""
  })
  
  // same function can be used to update multiple values in the state
  const handleChange = (evt) => {

Harshmakadia

const App = () => {
  const [state, setState] = useStateCallback(0); // same API as useState + setState with cb

  const handleClick = () => {
    setState(
      prev => prev + 1,
      // 2nd argument is callback , `s` is *updated* state
      // Hey that state is set successfully what do you
      // want to do, I'm callback your friend 😄
      s => console.log("I am called after setState, state:", s)

Harshmakadia

// time and time end
console.time("This");
let total = 0;
for (let j = 0; j < 10000; j++) {
  total += j
}
console.log("Result", total);
console.timeEnd("This");

// Memory

Harshmakadia

import React, { useState, useEffect } from "react";
import ReactDOM from "react-dom";

import "./styles.css";

function GithubCommit() {
  const [page, setPage] = useState(1);
  const [commitHistory, setCommitHistory] = useState([]);
  const [isLoading, setIsLoading] = useState(true);

Harshmakadia

import React from "react";
import ReactDOM from "react-dom";

import "./styles.css";

class GithubCommit extends React.Component {
  constructor() {
    super();
    this.state = {
      commitHistory: [],

Harshmakadia

// Method to addProductToCart
<div>
  <button
    onClick={context.addProductToCart.bind(this, product)}
  >
    Add to Cart
  </button>
</div>

// Method to removeProductFromCart

Harshmakadia

import React, { Component } from 'react';

import ShopContext from './shop-context';

class GlobalState extends Component {
  state = {
    products: [
      { id: 'p1', title: 'React 16 Sticker + T-shirt', price: 29.99 },
      { id: 'p2', title: 'Vue.js T-shirt', price: 9.99 },
      { id: 'p3', title: 'Angular T-shirt', price: 8.99 },

Harshmakadia

import ShopContext from '../context/shop-context'

class CartPage extends Component {
  static contextType = ShopContext

  componentDidMount() {
    // Some advantage of static contextType: We can now also access Context in the rest of the component
    console.log(this.context)
  }

Harshmakadia

import React, { Component } from 'react';
import ShopContext from '../context/shop-context';
import Navigation from '../components/navigation';
import './product.css';

class ProductsPage extends Component {
  render() {
    return (
      <ShopContext.Consumer>
        {context => (