JSFiddle - React, Tailwind, and code Playground

HTML

<canvas id="canvas"></canvas>

CSS

#canvas {
    background-color: yellow;
   
}

JavaScript

function windowsize(){
    var ctx = document.getElementById("canvas");
    ctx.width = window.innerWidth;
    ctx.height = window.innerHeight;
}
windowsize();

/*
function windowsize() {
WIDTH = $("#canvas")[0].width = ($(window).width()-20.5);
HEIGHT = $("#canvas")[0].height = ($(window).height()-20.5);

}

windowsize();
*/