Function ensureNonEmptyIterable

    • Ensures that a given value is a non-empty iterable.

      - If the value is not iterable → returns `undefined`.
      - If the value is an iterable but contains no entries → returns `undefined`.
      - If the value is a non-empty iterable → returns a fresh iterable (generator) that yields the first peeked value
      followed by the remaining values. This guarantees restartable iteration even when the original iterable is a
      one-shot generator.

      This function is ideal when you need a safe, non-empty iterable for iteration but cannot consume or trust the original iterable’s internal iterator state.

      Type Parameters

      • T

      Parameters

      • value: Iterable<T, any, any>

        The value to inspect.

      Returns Iterable<T, any, any>

      A restartable iterable containing all values, or undefined if the input was not iterable or contained no items.

      const iter = ensureNonEmptyIterable(['a', 'b']);
      // `iter` is an iterable yielding 'a', 'b'.

      const empty = ensureNonEmptyIterable([]);
      // `undefined`

      const gen = ensureNonEmptyIterable((function*(){ yield 1; yield 2; })());
      // Safe: returns an iterable yielding 1, 2 without consuming the generator.

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