Why my date don't change according my timezone?-CodePudding

I'm trying to make my data stay in Brazil's time zone, but every time I try to change it, when I give a console it shows the correct date, but as soon as I send it to my backend the date changes the timezone completely, I just need get today's date, but as there is a time zone, at 9 pm the day changes to the next day, what am I doing wrong? I tried this code here.

let date = new Date();

//this simulates the time after 21:00, just change the 15 to the number of hours needed so that the time is like after 21:00 to test (now is 8 am in Brazil)
date.setHours(date.getHours()   15);

date = date.toISOString().split('T')[0];

$('#date').append(date.toLocaleString("pt-BR"));

<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.6.0/jquery.min.js"></script>
</head>

<div id="date">
</div>

CodePudding user response：

Date.toISOString() will give you the UTC time as an ISO string.

If you want to get your local date as an ISO string, this is easy to do, using the Date.getFullYear(), Date.getMonth() and Date.getDate() values.

We create an array with the [year, month, day] values in it, then use String.padStart() and String.join() to create the ISO date.

This will give the correct day of year in the local timezone.

function getIsoDate(date) {
    const ymd = [ date.getFullYear(), date.getMonth()   1, date.getDate() ];
    return ymd.map(s => (s   '').padStart(2, '0')).join('-');
}

console.log(getIsoDate(new Date()));
console.log(getIsoDate(new Date('2022-10-19T22:30:00')));
console.log(getIsoDate(new Date('2022-10-19T00:00:00')));

.as-console-wrapper { max-height: 100% !important; }

A simple hack that will also work is using Date.toLocaleDateString() with the locale argument set to 'sv', this is because this language displays dates using the ISO format.

function getIsoDate(date) {
    return date.toLocaleDateString('sv');
}

console.log(getIsoDate(new Date()));
console.log(getIsoDate(new Date('2022-10-19T21:30:00')));

.as-console-wrapper { max-height: 100% !important; }