no-copy-frontend/src/app/lib/pluralize.ts

export const pluralize = (number: number, one: string, few: string, many: string) => {
	const currentLang = document.documentElement.getAttribute('lang') || 'ru';

	if (currentLang === 'ru') {
		const n = Math.abs(number) % 100;
		const n1 = n % 10;

		if (n > 10 && n < 20) return many; // 11-19
		if (n1 > 1 && n1 < 5) return few;  // 2-4 (кроме 12-14)
		if (n1 === 1) return one;  // 1 (кроме 11)

		return many; // 0, 5-9, 10-20, 25-30 и т.д.
	} else {
		if (number === 1 || number === 0) return one;
		return many;
	}
};