function onlyx()

in src/c/select.php [329:361]

• 32 lines of code
• 5 McCabe index (conditional complexity)

function onlyx<T>(
  Traversable<T> $traversable,
  ?Str\SprintfFormatString $format_string = null,
  mixed ...$format_args
)[]: T {
  $first = true;
  $result = null;
  foreach ($traversable as $value) {
    invariant(
      $first,
      '%s',
      $format_string === null
        ? Str\format(
          'Expected exactly one element%s.',
          $traversable is Container<_>
            ? ' but got '.count($traversable)
            : '',
        )
        : \vsprintf($format_string, $format_args),
    );
    $result = $value;
    $first = false;
  }
  invariant(
    $first === false,
    '%s',
    $format_string === null
      ? 'Expected non-empty Traversable.'
      : \vsprintf($format_string, $format_args),
  );
  /* HH_FIXME[4110] $first is false implies $result is set to T */
  return $result;
}