React Basic Hooks - useEffects sample

HTML

<div id="root"></div>

CSS

body{
  background-color:grey
}

.booking-movie-container {
  margin: 20px 0;
}

.booking-movie-container select {
  background-color: #fff;
  border: 0;
  border-radius: 5px;
  font-size: 14px;
  margin-left: 10px;
  padding: 5px 15px 5px 15px;
  -moz-appearance: none;
  -webkit-appearance: none;
  appearance: none;
}

.booking-container {
  perspective: 1000px;
  margin-bottom: 30px;
}

.booking-seat {
  background-color: #ed0c6b82; ;
  height: 25px;
  width: 25px;
  margin: 3px;
  border-top-left-radius: 10px;
  border-top-right-radius: 10px;
}

.booking-seat.booking-selected {

    
    background-color: #fd3c3c;
}


.walking-space{
  margin-right: 2%;
}


.booking-seat.booking-occupied {
  background-color: #fff;
}

/* .booking-seat:nth-of-type(2) {
  margin-right: 18px;
}

.booking-seat:nth-last-of-type(2) {
  margin-left: 18px;
} */

.booking-seat:not(.booking-occupied):hover {
  cursor: pointer;
  transform: scale(1.2);
}

.booking-showcase .booking-seat:not(.booking-occupied):hover {
  cursor: default;
  transform: scale(1);
}

.booking-showcase {
  background: rgba(0, 0, 0, 0.1);
  padding: 5px 10px;
  border-radius: 5px;
  color: #777;
  list-style-type: none;
  display: flex;
  justify-content: space-between;
}
.count{
    background-color: linear-gradient(to right, #ee7724, #d8363a, #dd3675, #b44593) !important;
}
.booking-showcase li {
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 10px;
}

.booking-showcase li small {
  margin-left: 2px;
}

.booking-row {
  display: flex;
  justify-content: center;
}

.booking-screen {
  background-color: #fff;
  height: 70px;
  width: 100%;
  margin: 15px 0;
  transform: rotateX(-45deg);
  box-shadow: 0 3px 10px rgba(255, 255, 255, 0.7);
}

p.text {
  margin: 5px 0;
}

p.text span {
  color: #6feaf6;
}

.screen-design{
    margin-top:-1%
}

React

const {useState, useEffect} = React;
  const row = 25;
    const seating =[25,25]
    const lastSeat =55;

function Example() {
  const [count, setCount] = useState(0);

  // Similar to componentDidMount and componentDidUpdate:  
  
  return (
   <div className="container screen-design">
        <br></br>
        <div>

        </div>
        <div className="booking-movie-container">
            <label>Pick a movie:</label>
            <select>
                <option value="10">Avengers: Endgame ($10)</option>
                <option value="12">Joker ($12)</option>
                <option value="8">Toy Story 4 ($8)</option>
                <option value="9">The Lion King ($9)</option>
            </select>
        </div>
        <ul className="booking-showcase">
            <li>
                <div className="booking-seat"></div>
                <small>N/A</small>
            </li>
            <li>
                <div className="booking-seat booking-selected"></div>
                <small>booking-selected</small>
            </li>
            <li>
                <div className="booking-seat booking-occupied"></div>
                <small>booking-occupied</small>
            </li>
        </ul>
        <div className="booking-container">
            <div className="booking-screen"></div>

            {Array.from({ length: row }, (rowelement, rowIndex) => <div className='booking-row'>
                {Array.from({ length: seating.length }, (columnelement, columnIndex) => {
                    debugger;
                    return <div className='walking-space'>
                        <div className='booking-row'>
                            {Array.from({ length: seating[columnIndex] }, (columnelement, columnIndex) => {
                                return <div className="booking-seat"></div>
                            })}
                        </div>
                    </div>
                })}
            </div>)}
            <div...