let draw =
  () {
    case Dom.Canvas.fromDomElement(canvas) {
      Maybe::Just(el) =>
        {
          el
          |> Canvas.setFont("30px serif")
          // Default letter spacing
          el
          |> Canvas.fillText("Hello world (default: 0px)", 10, 40)
          // Custom letter spacing: 10px
          el
          |> Canvas.setLetterSpacing(10)
          |> Canvas.fillText("Hello world (10px)", 10, 90)
          // Custom letter spacing: 20px
          el
          |> Canvas.setLetterSpacing(20)
          |> Canvas.fillText("Hello world (20px)", 10, 140)
          ""
        }
      Maybe::Nothing =>
        ""
    }
  }
{
  await Timer.timeout(0)
  draw()
}
<canvas as canvas width="700"/>