code: function shouldAddCurrentValue ({items, valueRecord, labelAttribute, valueAttribute, filter}) {
    const filterRegex = new RegExp(filter, 'i')
    const valueRecordMatchesFilter = filterRegex.test(valueRecord.get(labelAttribute))
    const itemsContainsValueRecord = items.find(item => item.value === valueRecord.get(valueAttribute))
    return valueRecordMatchesFilter && !itemsContainsValueRecord
  }
docs: Determine whether or not valueRecord should be appended to data
  @param {Object[]} items - the larger set of data
  @param {EmberObject} valueRecord - the record to add or not
  @param {String} labelAttribute - dot notated path to label attribute in record
  @param {String} valueAttribute - dot notated path to value attribute in record
  @param {String} filter - the partial match query filter to populate
  @returns {boolean} true if valueRecord should be added to items