2627-debounce.ts

// Title: Debounce
// Description:
//     Given a function fn and a time in milliseconds t, return a debounced version of that function.
//     A debounced function is a function whose execution is delayed by t milliseconds and whose execution is cancelled if it is called again within that window of time.
//     The debounced function should also receive the passed parameters.
//     For example, let's say t = 50ms, and the function was called at 30ms, 60ms, and 100ms.
//     The first 2 function calls would be cancelled, and the 3rd function call would be executed at 150ms.
//     If instead t = 35ms, The 1st call would be cancelled, the 2nd would be executed at 95ms, and the 3rd would be executed at 135ms.
// Link: https://leetcode.com/problems/debounce/

type F = (...p: any[]) => any;

function debounce(fn: F, t: number): F {
  let timeoutId = null;

  return function (...args) {
    if (timeoutId !== null) {
      clearTimeout(timeoutId);
      timeoutId = null;
    }

    timeoutId = setTimeout(() => {
      fn.apply(this, args);
    }, t);
  };
}

/**
 * const log = debounce(console.log, 100);
 * log('Hello'); // cancelled
 * log('Hello'); // cancelled
 * log('Hello'); // Logged at t=100ms
 */