Create AntiFool Button

set_sensitivity.ts

function setSensitivity(element: HTMLElement, callback: () => void, timeout: number = 500): void {
  let sensitivityTimer: number;

  element
    .addEventListener('mousedown', () => {
      sensitivityTimer = setTimeout(callback, timeout);
    });

  element
    .addEventListener('mouseup', () => {
      clearTimeout(sensitivityTimer);
    });
}

You could pass callback to setTimeout without wrapping it into additional arrow function (since callback is already a function)
sensitivityTimer = setTimeout(callback, timeout)
Overall LGTM

You could pass callback to setTimeout without wrapping it into additional arrow function (since callback is already a function)
sensitivityTimer = setTimeout(callback, timeout)

Thanks! You're right, I overdid it a bit. Made changes.