Get array of N previous months before a month

getPreviousMonths.js

const monthsLabels = [
  'January',
  'February',
  'March',
  'April',
  'May',
  'June',
  'July',
  'August',
  'September',
  'October',
  'November',
  'December',
];

const getPreviousMonths = (current, previous) => {
  const startMonth = (current - (previous % 12) + 13) % 12;
  const months = [];
  for (let i = 0; i < previous; i++) {
    months.push(monthsLabels[(startMonth + i) % 12]);
  }
  return months;
};

// Example call
// Get array of 20 months before April
getPreviousMonths(3, 20)