code: function transformValueMap(collection, path, transformer) {
      _.each(collection, (element) => {
          let val = _.get(element, path);
  
          if (!_.isUndefined(val)) {
              _.set(element, path, transformer(val));
          }
      });
  
      return collection;
  }
docs: Transforms a value in each element of collection if the path is not undefined.
  
  @static
  @memberOf _
  @category Array
  @param {Array} collection Array of objects
  @param {string} path The path of the value to transform
  @param {function} transformer Callback which returns the transformed value
  @return {Array} Returns the array of results.