on the window resizes, recalculate the canvas width as well, using a debounce to avoid calling too many times our canvas resizing

debounce-resize-event.js

const canvas = document.querySelector('canvas')

const debounce = (func) => {
  let timer
  return (event) => {
    if (timer) { clearTimeout(timer) }
    timer = setTimeout(func, 100, event)
  }
}

window.addEventListener('resize', debounce(() => {
  canvas.width = window.innerWidth
  canvas.height = window.innerHeight
}))