react-datetime-picker/src/shared/dates.ts

A date range picker for your React app.

import type { AmPmType } from './types.js';

export function convert12to24(hour12: string | number, amPm: AmPmType): number {
  let hour24 = Number(hour12);

  if (amPm === 'am' && hour24 === 12) {
    hour24 = 0;
  } else if (amPm === 'pm' && hour24 < 12) {
    hour24 += 12;
  }

  return hour24;
}

export function convert24to12(hour24: string | number): [number, AmPmType] {
  const hour12 = Number(hour24) % 12 || 12;

  return [hour12, Number(hour24) < 12 ? 'am' : 'pm'];
}