computeFieldType = (value, key = null) => {
  let type = 'simple';
  const specialKeys = ['tags', 'categories'];
  if (specialKeys.includes(key) && _.isArray(value)) return type;

  if (_.isObject(value)) type = 'object';
  if (_.isArray(value)) type = 'array';
  return type;
}
Given a field-value and corresponding key, this utility returns
metadata type for the pair.
@param {*} value
@param {String} key
@return {String} type