letIterableOrNone<T extends Object> function

Option<Iterable<Option<T>>> letIterableOrNone<T extends Object>(dynamic input)

Converts input to Iterable<Option<T>>, returning None on failure.

Supported types:

• Any sync Outcome chain.
• bool
• num
• double
• int
• String
• DateTime
• Uri,
• Iterable (dynamic)
• List (dynamic)
• Set (dynamic)
• Map (dynamic, dynamic)

Implementation

Option<Iterable<Option<T>>> letIterableOrNone<T extends Object>(dynamic input) {
  if (input is Outcome) {
    return switch (input.rawSync().value) {
      Ok(value: final okValue) => letIterableOrNone(
          NoStackOverflowWrapper(okValue),
        ),
      Err() => const None(),
    };
  }
  return switch (input is NoStackOverflowWrapper ? input.value : input) {
    // Materialize eagerly so the returned iterable is safe to iterate
    // multiple times and so a single-pass source (custom Iterable whose
    // `.iterator` getter throws after first use) is consumed exactly once.
    final Iterable<dynamic> i => Some(
        i.map((e) => letOrNone<T>(e)).toList(growable: false),
      ),
    final String s => jsonDecodeOrNone<Iterable<dynamic>>(
        s,
      ).map((i) => i.map((e) => letOrNone<T>(e)).toList(growable: false)),
    _ => const None(),
  };
}