I have the following function which should read time in UTC and return in local time, and sometimes it adds 2 hours(correctly) and sometimes 4 hours. Why is that? What can be the reason?
value = time in UTC
toLocalDate(value) {
let string = new Date(value);
let date = new Date();
date.setUTCFullYear(string.getFullYear(), string.getMonth(), string.getDate());
date.setUTCHours(string.getHours(), string.getMinutes(), string.getSeconds(), 0);
return date;
}
Example data:
Value: 2017-08-23T06:00:00
Expected output: Wed Aug 23 2017 08:00:00 GMT+0200 (Central European Daylight Time)
Output: Wed Aug 23 2017 10:00:00 GMT+0200 (Central European Daylight Time)
On some devices(like my phone or computer) it returns the expected output.
On my friend's device(mobile) it returns the second output.
Related
i am struggling with my code, new Date() convert my value to next day 1 hour
new Date('2013-03-27T23:59:59.999Z') // => Thu Mar 28 2013 00:59:59 GMT+0100
As a Solution:
new Date('2013-03-27T23:59:59.999Z'.replace(/-/g, '\/').replace(/T.+/, '')) // => Wed Mar 27 2013 00:00:00 GMT+0100
Any suggestions how to get the correct date?
I have a SharePoint list with delivery date column. I have created a table to display current week and next week delivery items using javascript. Everything works fine but for couple of team members Thursday delivery items are displaying in Wednesday cell and Friday items in Thursday cell.
I am not sure why it is happening. Can anyone help me out to resolve this issue? Any help would be greatly appreciated.
Here is my code. Added alerts to verify data, I am wondering why in second and third alerts sunday is showing Monday date and in third alert monday is showing Tuesday date. Added alert messages at the bottom. Please advice.
today = moment();
sundayDate = new Date(today.startOf('week'));
sundayShortDate = sundayDate.toLocaleDateString();
sundayTitle = getFormattedDate(sundayDate);
window.alert("sundayDate ::"+sundayDate+"");
monDate = new Date(sundayDate.setDate(sundayDate.getDate() + 1));
monSDate = monDate.toLocaleDateString();
monTitle = getFormattedDate(monDate);
window.alert("sundayDate ::"+sundayDate+"; monDate::"+monDate+"");
tueDate = new Date(monDate.setDate(monDate.getDate() + 1));
tuesSDate = tueDate.toLocaleDateString();
tueTitle = getFormattedDate(tueDate);
window.alert("sundayDate ::"+sundayDate+"; monDate::"+monDate+"; tueDate::"+tueDate+"");
First window alert:
sundayDate ::Sun Aug 16 2020 00:00:00 GMT-0400 (Eastern Daylight Time)
Second Alert:
sundayDate ::Mon Aug 17 2020 00:00:00 GMT-0400 (Eastern Daylight Time); monDate::Mon Aug 17 2020 00:00:00 GMT-0400 (Eastern Daylight Time)
Third Alert:
sundayDate ::Mon Aug 17 2020 00:00:00 GMT-0400 (Eastern Daylight Time); monDate::Tue Aug 18 2020 00:00:00 GMT-0400 (Eastern Daylight Time); tueDate::Tue Aug 18 2020 00:00:00 GMT-0400 (Eastern Daylight Time)
As was already commented, you are mutating the dates with calls to setDate().
As you already use moment, don't switch back to Date objects, but stick to moment objects.
For example:
let today = moment();
let fmt = "dddd, MMMM Do YYYY";
let sunDate = today.startOf('week');
let sunShortDate = sunDate.format(fmt);
let monDate = sunDate.clone().add(1, "day");
let monShortDate = monDate.format(fmt);
let tueDate = monDate.clone().add(1, "day");
let tueShortDate = tueDate.format(fmt);
console.log({ sunShortDate, monShortDate, tueShortDate });
<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.15.0/moment.min.js"></script>
Just like Date objects, also moment objects are mutable, and so you should call clone first before calling add.
You set sundayDate to sundayDate.setDate(sundayDate.getDate() + 1)
You should do:
monDate = new Date(sundayDate.getDate() + 1);
P.S.
I'm not sure if mixing moment.js and js Date is a good idea.
I am trying to convert the number of days since Jan 01 1970 to JavaScript Date.
Here is the code snippet.
new Date(864e5 * parseInt(data[i].d));
//here data[i].d contains number of days.
I checked all the data by this.
console.log(typeof(data[i].d), data[i].d);
//prints
number 17674
but sometimes it unable to convert it into date.
Invalid Date {}
while for
number 17858
//outputs.
Fri Aug 17 2018 05:00:00 GMT+0500 (Pakistan Standard Time)
Thanks for your time.
You just have to add the number of days times the milliseconds in a day, like so:
var originalDay = new Date(864e5)
console.log(originalDay) //Thu Jan 01 1970 19:00:00 GMT-0500 (Eastern Standard Time)
var numOfDays = 7
var daysSince = new Date(864e5 + parseInt(numOfDays * 864e5))
console.log(daysSince) //Thu Jan 08 1970 19:00:00 GMT-0500 (Eastern Standard Time) --7 days later
To make this work for you, you would just have to replace that numOfDays with the values in your array.
I want to create an array that contains unique months (August 2015, September 2015 etc.). For this I defined the following function that takes an object with timestamps as keys:
export function getUniqueMonths(exps) {
//1. get all keys from expenditures
const days = Object.keys(exps)
//2. convert key strings to timestamps
const daysInt = days.map((day) => (new Date(parseInt(day))))
//3. return only the "date portion" of the timestamp
const datePortion = daysInt.map((day) => (new Date(day.toDateString()) ))
//4. set each datePortion to 1st of month
const firstOfMonth = datePortion.map((day) => new Date(day.getFullYear(), day.getMonth(), 1) )
//5. keep only unique firstOfMonths
const uniqMonths = [...(new Set(firstOfMonth))]
return uniqMonths
}
However, this function gives me an array like this:
[Sat Aug 01 2015 00:00:00 GMT+0300 (Eastern European Summer Time), Sat Aug 01 2015 00:00:00 GMT+0300 (Eastern European Summer Time), Tue Sep 01 2015 00:00:00 GMT+0300 (Eastern European Summer Time), Sat Aug 01 2015 00:00:00 GMT+0300 (Eastern European Summer Time), Sat Aug 01 2015 00:00:00 GMT+0300 (Eastern European Summer Time), ...]
I thought getting the date portion of the timestamp (step 3) and setting all dates to first of month (step 4) would do the trick. But I still have duplicates in my array.
What am I missing?
I think you might be overengineering things :) Something like
function getUniqueMonths(exps) {
const uniqueMonths = new Set();
Object.keys(exps).forEach((timestamp) => {
const date = new Date(parseInt(timestamp)); // expected to be milliseconds since 1/1/1970
uniqueMonths.add(`${date.getFullYear()}-${date.getMonth()}`);
});
return uniqueMonths;
}
should get you a Set of unique months in the form of ['2017-12', '2018-0', ...] (zero-based months as is the JavaScript standard).
If you need Date objects, those are trivial to "rehydrate".
Two Date objects are not the same object, even if they contain the same timestamp.
Instead, try:
//3. keep the year-month portion of the date
const yearMonths = daysInt.map(day => day.getFullYear()+"-"+day.getMonth());
Then you can skip 4 and just get the unique year-months from there. These will be returned as "2015-7" for August 2015, for example.
I have some interesting problem and can't find the solution. Look at this:
var d1 = new Date("07 31 2014");
document.write(d1);
document.write('<br />');
var d2 = new Date(1406746800 * 1000);
document.write(d2);
when I run this script I get this result:
Thu Jul 31 2014 00:00:00 GMT+0500 (UZT)
Thu Jul 31 2014 00:00:00 GMT+0500 (UZT)
then after I changed my time zone I get this result:
Thu Jul 31 2014 00:00:00 GMT-0800 (AKDT)
Wed Jul 30 2014 11:00:00 GMT-0800 (AKDT)
as you can see the second result is Jul 30, but first result is Jul 31. I think they must both be equal to 31 Jul. I know this problem depends on the timezone but is there a solution?
So the constructor parameter is:
an Integer value representing the number of milliseconds since 1
January 1970 00:00:00 UTC
So given your integer value, that represents (for me, in BST):
Wed Jul 30 2014 20:00:00 GMT+0100
Which is
Wed Jul 30 2014 19:00:00 UTC
And your timezone is GMT-8, so thats the above -8 which gives:
Wed Jul 30 2014 11:00:00 GMT-0800 AKDT
The date string constructor constructs the date in your local timezone. You can see what the value should be by doing this:
new Date("07 31 2014").getTime() / 1000
Which returns 1406761200, not 1406746800