code: function fromPairs(pairs) {
        var index = -1,
            length = pairs == null ? 0 : pairs.length,
            result = {};
  
        while (++index < length) {
          var pair = pairs[index];
          result[pair[0]] = pair[1];
        }
        return result;
      }
docs: The inverse of `_.toPairs`; this method returns an object composed
  from key-value `pairs`.
  
  @static
  @memberOf _
  @since 4.0.0
  @category Array
  @param {Array} pairs The key-value pairs.
  @returns {Object} Returns the new object.
  @example
  
  _.fromPairs([['a', 1], ['b', 2]]);
  // => { 'a': 1, 'b': 2 }