/**
 * Checks the rows of a list query, for the services. Every service answers a
 * row that doesn't have its table's shape with a 500 rather than leaving it
 * out, so that damage shows instead of making items silently vanish.
 *
 * @module
 */

import { APIException } from "../lib/api-exception.ts";

/**
 * Returns `rows` turned by `toApi`, once `isRow` has accepted each.
 *
 * @throws {APIException} 500 when a row doesn't pass `isRow`.
 */
export function parseRows<R, T>(
  rows: unknown[],
  isRow: (row: unknown) => row is R,
  toApi: (row: R) => T,
): T[] {
  if (!rows.every(isRow)) {
    throw new APIException(500, "Malformed data in the database");
  }
  return rows.map(toApi);
}