Pluralize: 1 item, 2 items, 5 items / 1 элемент, 2 элемента, 5 элементов

pluralize.js

export const pluralize = (number, cases) => {
    number = Math.abs(number);
    return cases[number % 100 > 4 && number % 100 < 20 ? 2 : [2, 0, 1, 1, 1, 2][number % 10 < 5 ? number % 10 : 5]];
};

pluralize.ts

export const pluralize = (n: number, cases: [string, string, string]): string => {
    n = Math.abs(n);
    return cases[n % 100 > 4 && n % 100 < 20 ? 2 : [2, 0, 1, 1, 1, 2][n % 10 < 5 ? n % 10 : 5]];
};