JSFiddle - React, Tailwind, and code Playground

HTML

<canvas width="200" height="200" id="canvas1">

JavaScript

var ctx = document.getElementById('canvas1').getContext('2d');
ctx.strokeStyle = 'black';

ctx.lineWidth = .25;

var right = true;
var x = 20;
function go()
{
    ctx.clearRect(0, 0, 500, 500);
    x += right? +0.1:-0.1;
    if(right && x == 100)
        right = false;
    else if(!right && x == 20)
        right = true;

    ctx.strokeRect(x, 5.5, 10, 20);

    requestAnimationFrame(go);
}

go();