Executes a function once within a specified time window

onceWithin.js

const once = (fun, timeoutInMilliseconds) => {
  let inProgress = false;
  
  setTimeout(() => {
    inProgress = false;
  }, timeoutInMilliseconds);
  
  return () => {
    if (inProgress) {
      return;
    }

    inProgress = true;
    fun();
  }
}