I use p5.js but with typescript.

The structure of a p5 project:

let sketch = (p: p5) => {
  
  p.setup = () => {setup(p)
  };

  p.draw = () => {draw(p)
  };
};

new p5(sketch);

After reading this I defined my function setup and draw like this:

let slider: p5.Element;

function setup(p: p5): void {
  p.createCanvas(400, 300);
  slider = p.createSlider(0, 50, 50 / 2);
  
}

function draw(p: p5): void {
  p.background(50);
  p.fill(255);
  p.noStroke();
  p.ellipse(slider.value(), 50 / 2, 50, 50);
}

the code works but vs code underline slider.value() in red. This is normal because inside the the function draw we don’t know if slider is instantiated or not.
I would like to know if there a better way to writ this code. A way that doesn’t make VS code print this error.