css.css

tbody td { white-space: nowrap; overflow: hidden; text-overflow: ellipsis;}
span.extra { font-size: 70%; opacity: 0.5; }
tr.small { color: #555; }
tr.medium { color: #550; }
tr.large { color: #a50;}
tr.huge { color: #f00; font-weight: bold;}

js.js

var tag = document.createElement("script");
tag.setAttribute("src", "https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.1.0/Chart.min.js");
document.head.appendChild(tag);

agent.container.appendChild(domBuilder([
  ["h1", "Disk Analyser"],
  ["table",
    ["thead",
      ["tr",
        ["th", "Size"],
        ["th", "Largest Files"]]],
    ["tbody$tbody"],
    ["thead",
      ["tr",
        ["th", "Total Size"],
        ["th", "Largest Paths"]]],
    ["tbody$tbody2"]],
], agent));

var onError = console.error.bind(console);
var root = "/";

agent.largefiles(root, 20, 1048576, onError, onUpdate)(onDone);

function onDone(err, list) {
  if (err) { throw err; }
  onUpdate(list);
  agent.container.appendChild(domBuilder(["p", "Done!"]));
}

function colors(size) {
  if (size < 10*1024*1024) return "small";
  if (size < 200*1024*1024) return "medium";
  if (size < 4*1024*1024*1024) return "large";
  return "huge";
}

function humanize(size) {
  return ["span", {title:size},
    size < 1024 ? size + "b" :
    size < 1024*1024 ? (Math.floor(size / 1024 * 10)/10) + "Kb" :
    size < 1025*1024*1024 ? (Math.floor(size / 1024 /1024 * 10)/10) + "Mb" :
    (Math.floor(size / 1024 /1024 / 1024 * 10)/10) + "Gb"];
}

function highlight(path) {
  var matches = path.match(/^(.*\/)([^\/]+)$/);
  
  return matches ? ["span", {title:path},
    ["span.extra", matches[1]],
    ["span.main", matches[2]],
  ] : path;
}

function onUpdate(list) {
  agent.tbody.textContent = "";
  agent.tbody.appendChild(domBuilder(list.map(function (entry) {
    return ["tr", {"class":colors(entry[1])},
      ["td", humanize(entry[1])],
      ["td", highlight(entry[0])]];
  })));
}

agent.diskusage(root, 4, 16777216, onEntry, onError)(onFinished);

function sorter(l, r) {
  return l[1] < r[1] ? 1 : l[1] > r[1] ? -1 : 0;
}

// Should eventually be able to compress multiple files at once
var compressFileFunction = function compressFile(fileName) {
  agent.exec("tar", {"args":{"-cvfz", fileName+".tar.gz", fileName}})
}

var deleteFileFunction = function deleteFile(path) {
  agent.rm(path, false)
}

function makeRecommendation(name, size) {
  // if name ends in .log recommend compression
  // not sure which instances we would recommend deletion
  // for now I could just pic a random number of set that function so that I can test things.
  if (Math.floor(Math.random())) {
    return compressFileFunction
  }
  return deleteFileFunction
}

var entries = [];
function onEntry(path, size) {
  entries.push([path,size]);
  entries.sort(sorter);
  agent.tbody2.textContent = "";
  agent.tbody2.appendChild(domBuilder(entries.slice(0,20).map(function (entry) {
    return ["tr", {"class":colors(entry[1])},
      ["td", humanize(entry[1])],
      ["td", highlight(entry[0])]];
  })));
}

function onFinished(err, exists) {
  if (err) { throw err; }
}

lua.lua

local agent = {}

agent.largefiles = largefiles
agent.diskusage = diskusage
agent.exec = exec
agent.rm = rm

return agent