//a simple date formatting function

function dateFormat(inputDate, format) {

    //parse the input date

    const date = new Date(inputDate);

​

    //extract the parts of the date

    const day = date.getDate();

    const month = date.getMonth() + 1;

    const year = date.getFullYear();    

​

    //replace the month

    format = format.replace("MM", month.toString().padStart(2,"0"));        

​

    //replace the year

    if (format.indexOf("yyyy") > -1) {

        format = format.replace("yyyy", year.toString());

    } else if (format.indexOf("yy") > -1) {

        format = format.replace("yy", year.toString().substr(2,2));

    }

​

    //replace the day

    format = format.replace("dd", day.toString().padStart(2,"0"));

​

    return format;

}

​

console.log('Converted date: '+ dateFormat('2021-12-10', 'MM-dd-yyyy'));