AI solution for JavaScript Coding Question on BFE.dev
4. implement basic throttle()

Here's one possible implementation of a basic throttle() function in JavaScript:

function throttle(func, delay) {
  let cooling = false;
  let lastArgs = null;

  return function(...args) {
    if (!cooling) {
      cooling = true;
      func.apply(this, args);
      setTimeout(() => cooling = false, delay);
    } else {
      lastArgs = args;
    }
  };
}

This implementation creates a closure around cooling, lastArgs, func, and delay. The returned function is the throttled version of func.

On each invocation of the throttled function, it checks whether it's in a "cooling" state. If not, it immediately calls func with the provided arguments and sets a timeout to reset the cooling state after delay milliseconds.

If the function is in a cooling state, it simply saves the arguments for later use. Note that this implementation always returns undefined, which means some calls to func might be silently dropped.

Here's how you could use it:

const throttledLog = throttle(console.log, 1000);

throttledLog(1); // logs 1 immediately
throttledLog(2); // is ignored
throttledLog(3); // is ignored

setTimeout(() => throttledLog(4), 500); // logs 4 after 500ms
setTimeout(() => throttledLog(5), 1000); // logs 5 after 1000ms