Function composeAsyncValidators

packages/forms/src/validators.ts:706–712

(
  validators: Array<AsyncValidator | AsyncValidatorFn>,
)

 * them into a single validator function.
 */
export function composeAsyncValidators(
  validators: Array<AsyncValidator | AsyncValidatorFn>,
): AsyncValidatorFn | null {
  return validators != null
    ? composeAsync(normalizeValidators<AsyncValidatorFn>(validators))
    : null;
}

/**
 * Merges raw control validators with a given directive validator and returns the combined list of