a function to get all dates surrounding a given date - it is intended to use when building calendars with 42 cells

getDates.ts

  getDates(date: Date): Date[] {
    const dates: Date[] = [];
    const firstDate: Date = new Date(new Date(date).setDate(1));
    const firstDateDay: number = firstDate.getDay();
    const daysBeforeFirst: number = firstDateDay - 1 === -1 ? 6 : firstDateDay - 1;

    for (let i = daysBeforeFirst - 1; i >= 0; i--) {
      dates.push(new Date(new Date(date).setDate(-i)));
    }

    const month: number = date.getMonth();
    const lastDate: number = new Date(new Date(new Date(date).setMonth(month + 1)).setDate(0)).getDate();

    for (let i = 1; i <= lastDate; i++) {
      dates.push(new Date(new Date(date).setDate(i)));
    }

    const cellCount: number = 42;

    for (let i = dates.length, j = 1; i < cellCount; i++, j++) {
      dates.push(new Date(new Date(new Date(date).setMonth(month + 1)).setDate(j)));
    }

    return dates;
  }