1function throttle(func, waitTime) {
2  // Set isThrottling flag to false to start
3  // and savedArgs to null
4  let isThrottling = false,
5    savedArgs = null;
6  // Spread the arguments for .apply
7  return function (...args) {
8    // Return a wrapped function
9    // Flag preventing immediate execution
10    if (!isThrottling) {
11      // Actual initial function execution
12      func.apply(this, args);
13      // Flip flag to throttling state
14      isThrottling = true;
15      // Queue up timer to flip the flag so future iterations can occur
16      function queueTimer() {
17        setTimeout(() => {
18          // Stop throttling
19          isThrottling = false;
20          // Queueing up the next invocation after wait time passes
21          if (savedArgs) {
22            func.apply(this, savedArgs);
23            isThrottling = true;
24            savedArgs = null;
25            queueTimer();
26          }
27        }, waitTime);
28      }
29      queueTimer();
30    }
31    // Wait state until timeout is done
32    // Save arguments
33    else savedArgs = args;
34  };
35}