when run on a facebook friends list, outputs a list of families

fb_friends_2_families.js

var by_name = {};

function url2names(u) {
  var url_name = u.match(/\.com\/[^?#\\.]+\.([^?#\/]+)/)
  if (!url_name || url_name[1] === 'php') {
    return [];
  }
  return url_name[1].replace(/\d/g, '').replace(/\.$/, '').replace(/-/g, '.').split('.');
}

function add(display_name, names) {
  names.forEach(function(name){
    if (name.length > 1) {
      if (typeof by_name[name] === 'undefined') {
        by_name[name] = [];
      }
      by_name[name].push(display_name);
    }
  });  
}

add(document.querySelector('#fb-timeline-cover-name a').textContent, url2names(location.href));

var people = document.querySelectorAll('._3i9')[0].querySelectorAll('.fcb a');
for (var i = 0; i < people.length; i++) {
  var display_name = people[i].textContent;
  var names = url2names(people[i].getAttribute('href'));
  display_name.toLowerCase().replace(/^.+ /, '').replace(/-/g, ' ').split(' ').forEach(function(name){
    if (names.indexOf(name) === -1){
      names.push(name);
    }
  });
  add(display_name, names);
}

var sorted = [];
for (var name in by_name) {
  if (by_name[name].length > 1) {
    sorted.push([name, by_name[name]]);
  }
}
sorted.sort(function(a, b){
  return a[1].length - b[1].length;
});
sorted.forEach(function(set){
  console.log(set[0] + ' (' + set[1].length + '): ' + set[1].join(', '));
});