code: function normalizeMap (map) {
    return Array.isArray(map)
      ? map.map(key => ({ key, val: key }))
      : Object.keys(map).map(key => ({ key, val: map[key] }))
  }
docs: Normalize the map
  normalizeMap([1, 2, 3]) => [ { key: 1, val: 1 }, { key: 2, val: 2 }, { key: 3, val: 3 } ]
  normalizeMap({a: 1, b: 2, c: 3}) => [ { key: 'a', val: 1 }, { key: 'b', val: 2 }, { key: 'c', val: 3 } ]
  @param {Array|Object} map
  @return {Object}