code: function normalizeDateFields (collection, preparedFields) {
    let dateFields = []
    if (collection && collection.metadata && collection.metadata.fields) {
      collection.metadata.fields.forEach((field, i) => {
        // If field is a Date and was included in requested fields (or requested fields are wildcard) add to array
        if (field.type === 'Date' && (preparedFields === undefined || preparedFields.indexOf(field.name) > -1)) {
          dateFields.push(field.name)
        }
      })
    }
    return dateFields
  }
docs: Identify Date-type fields and explicitly add to dateFields array if outFields query param contains
  the date field name or if outFields is a wildcard (when outFields=*, preparedFields === undefined)
  
  @param {Object} collection metadata about the data source
  @param String[] preparedFields - single element string array of delimited field names from "outFields" query param