Is still DRY working when we've copied that code?

Yes, I think so. Although the structure is exactly the same, the data sources and the values are different. For instance, the arrays are different, the class names are different, the ids are different. And, you have to create a new AJAX object for each new request.

If not, how would you get around it? If statements? I suppose...but it would be very cumbersome and maybe not very conventional if you were also working with other programmers. Plus, you'd still have to create separate AJAX objects, so it would be a lot of unnecessary work. That's my opinion anyway.

Also, it was so much more fun and easier to copy and paste!

I'd say if you were building something with huge number of AJAX requests that are broadly similar then you'd want to look at how you could break things into composable functions. e.g., a function to handle the AJAX request, pass it into another function that checks the status, another that creates the list items, another that injects this into the right DOM node.

But it's probably overkill for this example :)

I agree with Kristin, for the sake of clarity it stays better this way, and even if we were to create a function just for creating the ul, the amount of parameters would make it rather "clunky", like this:

function composeList(table, listClass, statusField, nameField, trueClass, falseClass) {    
  var statusHTML = '<ul class="' + listClass + '">';
  for (var i=0; i<table.length; i += 1) {
    if (table[i][statusField] === true) {
      statusHTML += '<li class="' + trueClass + '">';
    } else {
      statusHTML += '<li class="' + falseClass + '">';
    }
    statusHTML += table[i][nameField];
    statusHTML += '</li>';
  }
  statusHTML += '</ul>';
  return statusHTML;
}

var employees = new XMLHttpRequest();
employees.onreadystatechange = function () {
  if(employees.readyState === 4 && employees.status === 200) {
    var table = JSON.parse(employees.responseText);            
    document.getElementById('employeeList').innerHTML = composeList(table, 'bulleted', 'inoffice', 'name', 'in', 'out');
  }
};
employees.open('GET', '../data/employees.json');
employees.send();

var rooms = new XMLHttpRequest();
rooms.onreadystatechange = function () {
  if(rooms.readyState === 4 && rooms.status === 200) {
    var table = JSON.parse(rooms.responseText);            
    document.getElementById('roomList').innerHTML = composeList(table, 'rooms', 'available', 'room', 'empty', 'full');
  }    
};
rooms.open('GET', '../data/rooms.json');
rooms.send();

In the video. When Dave copied his code. Here is link https://teamtreehouse.com/forum/video:13072

Hey Maxim,

I'm going to say that yes, this is probably the best way to still use DRY programming. It's temping to think that you could probably make this all work with one function. Moreover; it would probably work. Although I would say it would only work in this context. If you wanted to create a universal function to handle any and all possible outcomes (ie. other than just a <ul> with X amount of <li>'s), I don not think it would be possible without being immensely complicated. I personally think this would be the best solution even with DRY programming in mind.

Hope that helps! Cale

Really interesting question! It's seems like, though, in the case of AJAX that the best practice is actually to separate out the code thusly. So I think this is a situation where clarity and maintainability are given priority over not repeating oneself.

Very Interesting ! First thing that popped into my mind was the DRY principle as well. Interesting comments , would love to see what a few of the treehouse teachers would have to say about this as well :D