How can I use SolidJS ref with typescript?

I want to create a ref to a canvas element:

export const Canvas = () => {
  let ref: HTMLCanvasElement;

  return <canvas ref={ref} width={500} height={500}></canvas>;
};

export const Canvas = () => {
  let ref: HTMLCanvasElement;

  return <canvas ref={ref} width={500} height={500}></canvas>;
};

But I keep getting TS error that "Variable

ref

ref

is being used without being assigned." What's the correct way to use refs with Typescript?