wilzbach/msa

const k = require("koala-js");

const Loader =

  // asynchronously require a script
  {loadScript: function(url, cb) {
    var s = k.mk("script");
    s.type = "text/javascript";
    s.src = url;
    s.async = true;
    s.onload = s.onreadystatechange = function() {
      if (!r && (!this.readyState || this.readyState === "complete")) {
        var r = true;
        return cb();
      }
    };
    var t = document.getElementsByTagName("script")[0];
    return t.parentNode.appendChild(s);
  },

  // joins multiple callbacks into one callback
  // a bit like Promise.all - but for callbacks
  joinCb: function(retCb, finalLength, finalScope) {
    finalLength = finalLength || 1;
    var cbsFinished = 0;

    var callbackWrapper = function(cb, scope) {
      if (!(typeof cb !== "undefined" && cb !== null)) {
        // directly called (without cb)
        return counter();
      } else {
        return (function() {
          var ref;
          if (ref = "apply", cb.indexOf(ref) >= 0) {
            cb.apply(scope, arguments);
          }
          return counter();
        });
      }
    };

    var counter = function() {
      cbsFinished++;
      if (cbsFinished === finalLength) {
        return retCb.call(finalScope);
      }
    };

    return callbackWrapper;
  }
  };
export default Loader;