Format a date string or date object using DayJS

formatDateAsYearMonthDay.js

import dayjs from 'dayjs'


// @param date {string, dayjs object}
// @param separator {string} optional - separates year/month/day numbers. Empty string is valid.

function formatDateAsYearMonthDay(date, separator = '-') {
    if (!(date instanceof dayjs || typeof date === 'string')) {
        return false // Unsupported date type. `undefined` is unsupported.
    }

    const parsedDate = date instanceof dayjs
        ? date
        : dayjs(date)

    if (parsedDate.isValid()) {
        return parsedDate.format(`YYYY${separator}MM${separator}DD`)
    }

    return false // date could not be parsed.
}

export default formatDateAsYearMonthDay