Throttle and debounce

gistfile1.txt

function throttle(delay, no_trailing, callback, debounce_mode) {
  var timeout_id,
    last_exec = 0;

  if ( typeof no_trailing !== "boolean" ) {
    debounce_mode = callback;
    callback = no_trailing;
    no_trailing = undefined;
  }

  function wrapper() {
    var that = this,
      elapsed = +new Date() - last_exec,
      args = arguments;

    function exec() {
      last_exec = +new Date();
      callback.apply( that, args );
    }

    function clear() { timeout_id = undefined; }

    if ( debounce_mode && !timeout_id ) { exec(); }

    timeout_id && clearTimeout( timeout_id );

    if ( debounce_mode === undefined && elapsed > delay ) {
      exec();
    }
    else if ( no_trailing !== true ) {
      timeout_id = setTimeout( debounce_mode ? clear : exec, debounce_mode === undefined ? delay - elapsed : delay );
    }
  }

  if ( $.guid ) {
    wrapper.guid = callback.guid = callback.guid || $.guid++;
  }

  return wrapper;
}

export { throttle };