Typescript Debounce

debounce.ts

// ts 3.6x
function debounce<T extends Function>(cb: T, wait = 20) {
    let h = 0;
    let callable = (...args: any) => {
        clearTimeout(h);
        h = setTimeout(() => cb(...args), wait);
    };
    return <T>(<any>callable);
}

// usage
let f = debounce((a: string, b: number, c?: number) => console.log(a.length + b + c || 0));
f("hi", 1, 1);
f("world", 1);

 debounce = <F extends (...args: Parameters<F>) => ReturnType<F>>(
  func: F,
  waitFor: number,
) => {
  let timeout: NodeJS.Timeout

  const debounced = (...args: Parameters<F>) => {
    clearTimeout(timeout)
    timeout = setTimeout(() => func(...args), waitFor)
  }

  return debounced
}

The timeout type should be ReturnType<typeof setTimeout>