code: function each (list, fn) {
    var i
    var len = list.length
    var idx
  
    if (typeof len === 'number') {
      for (i = 0; i < len; i++) {
        fn(list[i], i)
      }
    } else {
      idx = 0
      for (i in list) {
        if (list.hasOwnProperty(i)) {
          fn(list[i], i, idx++)
        }
      }
    }
  
    return list
  }
docs: each : each(list, fn)
  Iterates through `list` (an array or an object). This is useful when dealing
  with NodeLists like `document.querySelectorAll`.
  
  var each = require('dom101/each');
  var qa = require('dom101/query-selector-all');
  
  each(qa('.button'), function (el) {
  addClass('el', 'selected');
  });