You dont need Momentjs

Problem

The format I need: 2020-04-20T16:20:00+09:00

Some code smell I wrote :-ss

const standardizeDate = (date) => {
    date.setHours(date.getHours() + 9);
    return date.toISOString().slice(0, -5) + "+09:00";
}

This one looks much better:

<script src="https://unpkg.com/dayjs@1.8.21/dayjs.min.js"></script>

const standardizeDate = (date) => dayjs(date).format('YYYY-MM-DDTHH:mm:ssZ');
Performance concerns

Large bundle size

Shout out to You-Dont-Need-Momentjs and also dayjs