Implement debounce

A search box should not hit the network on every keystroke. Wait until the typing pauses, then send the latest query once.

Implement debounce(fn, wait).

It returns a new function. That function does not call fn immediately. It waits wait milliseconds. If it is called again before the wait ends, the timer starts over and the previous call is discarded. When the wait finally elapses, fn runs once, with the arguments from the most recent call.

With wait of 100:

const d = debounce((q) => search(q), 100)
d("c")
// 40ms pass: search has not run
d("ca")
// 100ms pass with no further calls
// search runs once, with "ca"

The grader moves time on a virtual clock. setTimeout, clearTimeout, and Date.now work. Time does not pass on its own, and setInterval is not available.

Requirements:

• fn is not called until wait ms elapse with no new calls.
• Several calls inside the window become exactly one call to fn.
• fn receives the arguments from the latest call.
• Each new call resets the timer.

Write a top-level function named debounce. Do not use export or module.exports.

Optional: a cancel() method on the returned function that drops a pending call. The required tests pass without it.