code: function map (list, fn) {
    var i
    var len = list.length
    var result = []
    var idx
  
    if (typeof len === 'number') {
      for (i = 0; i < len; i++) {
        result.push(fn(list[i], i))
      }
    } else {
      idx = 0
      for (i in list) {
        if (list.hasOwnProperty(i)) {
          result.push(fn(list[i], i, idx++))
        }
      }
    }
  
    return result
  }
docs: map : map(list, fn)
  Iterates through `list` (an array or an object).
  
  var map = require('dom101/map');
  var text = require('dom101/text');
  
  map(qa('.button'), function (el) {
  return text(el);
  });