JSFiddle - React, Tailwind, and code Playground

HTML

<canvas id="canvas1" width="500" height="500"></canvas>

JavaScript

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

//ctx.arc(x,y,radius,startAngle,endAngle, anticlockwise);  

ctx.beginPath()
ctx.arc(100,100,100,0,Math.PI, false); // outer (filled)
// the tip of the "pen is now at 0,100
ctx.arc(100,100,55,Math.PI,Math.PI*2, true); // outer (unfills it)
ctx.fill();