Sequential scripts loading with jQuery

gistfile1.txt

// This snippet depends on https://gist.github.com/ccbeea00dd952bbe7eb4

function getScripts(collection, endcallback){
  if(collection.length == 0){
    return endcallback && endcallback();
  }

  jQuery.getScript(collection[0], function(){
     getScripts(collection.slice(1), endcallback);
  });
}

function getScriptsAdvanced(collection, endcallback){
  if(!this.scriptsLoaded){
    this.scriptsLoaded = [];
  }

  if(collection.length == 0){
    return endcallback && endcallback();
  }

  var script = collection[0];
  var callback = function(){
    getScriptsAdvanced(collection.slice(1), endcallback);
  };

  if(this.scriptsLoaded.indexOf(script) == -1){
    this.scriptsLoaded.push(script);
    jQuery.getScript(script, callback);
  }else{
    callback();
  }
}


function withScripts(){
  var old$ = window.$;
  window.$ = jQuery;
  var scripts = Array.prototype.slice.call(arguments, 0, arguments.length - 1);
  var endcallback = arguments[arguments.length - 1];

  getScriptsAdvanced(scripts, function(){
    endcallback();
    window.$ = old$;
  });
}

This code is used in https://github.com/html/jquery-seq