*surrogatePairWithoutUFlag(chars) {
		for (const [index, char] of chars.entries()) {
			const previous = chars[index - 1];

			if (
				previous &&
				char &&
				isSurrogatePair(previous.value, char.value) &&
				!isUnicodeCodePointEscape(previous) &&
				!isUnicodeCodePointEscape(char)
			) {
				yield [previous, char];
			}
		}
	}
Each function returns matched characters if it detects that kind of problem.
@type {Record<string, (chars: Character[]) => IterableIterator<Character[]>>}