const canvas = document.getElementById("canvas"); 
canvas.width = window.innerWidth = 750;
canvas.height = 600;
var context = canvas.getContext("2d");
context.fillStyle = "white";
context.fillReact(0, 0, canvas.width, canvas.height);
let draw_color = "black";
let draw_width = "2";
let is_drawing = false;
canvas.addEventListener("touchstart", start, false);
canvas.addEventListener("touchmove", draw, false);
canvas.addEventListener("mousedown", start, false);
canvas.addEventListener("mousemove", draw, false);
function start(event) {
is_drawing = true;
context.beginPath();
context.moveTo(event.clientX = canvas.offsetLeft, event.clientY = canvas.offsetTop);
event.preventDefault();
}

function draw(event) {
if (is_drawing) {
    context.beginPath();
    context.moveTo(event.clientX = canvas.offsetLeft, event.clientY = canvas.offsetTop);

    context.strokeStyle = draw_color;
    context.lineWidth = draw_width;
    context.lineCap = "round";
    context.lineJoin = "round";
    context.stroke();
  }
} 

I did everything right yet it is showing context.fillReact is not a function, it should have draw a line on moving the cursor but it is not doing anything just showing the error.