Wrap functions to stagger (vs. lodash _.throttle, which drops throttled messages)

stagger.js

"use strict";

module.exports = function stagger(fn, ms) {
  let queue = [];
  let running = false;

  let flush = () => {
    if (queue.length === 0) {
      running = false;
      return;
    }

    running = true;
    
    setTimeout(() => {
      fn.apply(this, queue.shift());
      return flush();
    }, ms);
  };

  return function staggered() {
    let args = Array.prototype.slice.call(arguments);
    queue.push(args);
    if (!running) {
      return flush(queue);
    }
  };
};