Duolingo HOF extractor script

// HOF extractor script
//
// To be run at https://www.duolingo.com/comment/2933824
//
//
// The `user` object:
// user = {
//    name : '<name>',
//    streak: <streak duration>,
//    levels: {
//      <language>:<level>,
//      ...
//    }
//  }

// Sort list of `user` objects first by streak
// duration, then by username.
function sortByStreak(users){
  return users.sort(function(a, b){
    var c = b.streak - a.streak;
    if(c===0)
      c = b.name < a.name ? -1 : 1;
    return c;
  });
}

// `node` must be a <header> element with a
// child <a class=username>.
function extractUserName(node){
  return node.querySelector('a.username').innerHTML;
}

// `node` must be a <header> element.
function extractLevels(node){
  return undefined;
}

// `node` must be a <header> element.
function extractStreak(node){
  var streakIcon = node.querySelector('.icon-streak-micro');
  if(streakIcon)
    return parseInt(
             streakIcon
               .parentNode
               .textContent
             , 10);
    else
      return 0;
}

// Print segment of HOF. `users` is the list of user objects,
// `q` is the streak length required to qualify for this HOF segment,
// `start` is where to start looking in the `users` list.
// When it encounters a user that does not qualify, it returns
// the current list position.
function printHOFsegment(users,q,start){
  for (var i = start, m = users.length; i < m; i++){
    var user = users[i];
    if(user.streak < q)
      return i;
    console.log(user.streak,user.name);
  }
}

function printHallOfFame(users){
  var gold_q = 500;
  var silver_q = 400;
  var bronze_q = 365;
  var soon_to_be_q = 300;

  sortByStreak(users);
  console.log('Gold');
  var i = printHOFsegment(users,gold_q,0);
  console.log('Silver');
  i = printHOFsegment(users,silver_q, i);
  console.log('Bronze');
  i = printHOFsegment(users,bronze_q, i);
  console.log("Soon to be's");
  i = printHOFsegment(users,soon_to_be_q, i);
}

//
// Get the headers from all posts in this thread.
var nodeList = document.querySelectorAll('header > a.username');
var headers = [];
for(var i=0,m=nodeList.length; i<m;i++){
  headers.push(nodeList.item(i).parentNode);
}

// Just an object containing the usernames of users
// we already processed.
processed_users={};

// List of user objects.
users=[];

// Iterate through the headers, collecting data for
// each user as we go along.
for(var i=0,m=headers.length;i<m;i++){
  var n = headers[i];
  var name = extractUserName(n);
  if(name in processed_users) continue;
  var userData = {};
  var streak = extractStreak(n);
  userData.name = name;
  userData.streak = streak;
  users.push(userData);
  processed_users[name] = undefined;
}

printHallOfFame(users);