Incorrect time shown in Google LineChart - javascript

There are dates stored as timestamp in the MySQL database. If I view them with phpMyAdmin the correct time is shown. In a php script I try to output the date with UNIX_TIMESTAMP into a Javascript Date Object (new Date()). When displaying the data in a Google Chart there is a time offset of +2:00 hours (my current timezone). I also looked into the timestamp and a timestamp converter told me that the local time is correct and UTC time is -2:00 hours.
In the php-script I already set the timezone with date_default_timezone_set(). SELECT ##global.time_zone, ##session.time_zone; outputs SYSTEM. But I still get the time offset. Now I use
SELECT UNIX_TIMESTAMP(CONVERT_TZ(Timestamp, "+02:00", ##session.time_zone)) ...
and I get the correct data. Does this mean that the data is stored with a 2 hours offset? Why does phpMyAdmin showing me the correct date and time? Or does the Google chart expects UTC time and the browser automatically adds the difference for the timezone?
What is the real problem here?

Now I wrote a function which converts the timestamp from the database into an UTC date:
function getDateinUTC(timestamp){
var date = new Date(timestamp * 1000);
var year = date.getUTCFullYear();
var month = date.getUTCMonth() + 1; // getMonth() is zero-indexed, so we'll increment to get the correct month number
var day = date.getUTCDate();
var hours = date.getUTCHours();
var minutes = date.getUTCMinutes();
var seconds = date.getUTCSeconds();
return new Date(year, month, day, hours, minutes, seconds);
}
When I create the DataTable I simply call the function as shown here:
rows: [
{c:[{v:getDateinUTC(stamp)}, {v: value}]},
]
You have to replace stamp and value with your php-code which fills the place.
This idea is based on the article Automatic timezone conversion in JavaScript by David Mytton.
So far the times seems to be correct.

Related

Convert the CST time to local browser time [duplicate]

i am using moment for getting server time .
moment.tz.setDefault("Asia/Kolkata");
var now = new Date();
var _p_date = moment.tz(now, zone).format();
time when inserting _p_date = 2016-01-05T18:32:00+05:30
But in database date variable is type of DATETIME. and time is saved as 2016-01-05 18:32:00.
and after that when i comparing with this to get time_ago funcionality. providing me wrong estimation.
using time ago = moment("2016-01-05T18:32:00.000Z").fromNow(); // is showing In 5 hours
Since your initial timezone is lost you have to create moment.tz object with selected timezone. Try this plunker
var date = moment.tz(moment("2016-01-05T18:32:00.000Z", "YYYY-MM-DDTHH:mm")
.format('YYYY-MM-DD HH:mm'), 'Asia/Kolkata');
console.log(date.fromNow());

Incorrect time while copy pasting a date time value using google apps script [duplicate]

I'm trying to get from a time formatted Cell (hh:mm:ss) the hour value, the values can be bigger 24:00:00 for example 20000:00:00 should give 20000:
Table:
if your read the Value of E1:
var total = sheet.getRange("E1").getValue();
Logger.log(total);
The result is:
Sat Apr 12 07:09:21 GMT+00:09 1902
Now I've tried to convert it to a Date object and get the Unix time stamp of it:
var date = new Date(total);
var milsec = date.getTime();
Logger.log(Utilities.formatString("%11.6f",milsec));
var hours = milsec / 1000 / 60 / 60;
Logger.log(hours)
1374127872020.000000
381702.1866722222
The question is how to get the correct value of 20000 ?
Expanding on what Serge did, I wrote some functions that should be a bit easier to read and take into account timezone differences between the spreadsheet and the script.
function getValueAsSeconds(range) {
var value = range.getValue();
// Get the date value in the spreadsheet's timezone.
var spreadsheetTimezone = range.getSheet().getParent().getSpreadsheetTimeZone();
var dateString = Utilities.formatDate(value, spreadsheetTimezone,
'EEE, d MMM yyyy HH:mm:ss');
var date = new Date(dateString);
// Initialize the date of the epoch.
var epoch = new Date('Dec 30, 1899 00:00:00');
// Calculate the number of milliseconds between the epoch and the value.
var diff = date.getTime() - epoch.getTime();
// Convert the milliseconds to seconds and return.
return Math.round(diff / 1000);
}
function getValueAsMinutes(range) {
return getValueAsSeconds(range) / 60;
}
function getValueAsHours(range) {
return getValueAsMinutes(range) / 60;
}
You can use these functions like so:
var range = SpreadsheetApp.getActiveSheet().getRange('A1');
Logger.log(getValueAsHours(range));
Needless to say, this is a lot of work to get the number of hours from a range. Please star Issue 402 which is a feature request to have the ability to get the literal string value from a cell.
There are two new functions getDisplayValue() and getDisplayValues() that returns the datetime or anything exactly the way it looks to you on a Spreadsheet. Check out the documentation here
The value you see (Sat Apr 12 07:09:21 GMT+00:09 1902) is the equivalent date in Javascript standard time that is 20000 hours later than ref date.
you should simply remove the spreadsheet reference value from your result to get what you want.
This code does the trick :
function getHours(){
var sh = SpreadsheetApp.getActiveSpreadsheet();
var cellValue = sh.getRange('E1').getValue();
var eqDate = new Date(cellValue);// this is the date object corresponding to your cell value in JS standard
Logger.log('Cell Date in JS format '+eqDate)
Logger.log('ref date in JS '+new Date(0,0,0,0,0,0));
var testOnZero = eqDate.getTime();Logger.log('Use this with a cell value = 0 to check the value to use in the next line of code '+testOnZero);
var hours = (eqDate.getTime()+ 2.2091616E12 )/3600000 ; // getTime retrieves the value in milliseconds, 2.2091616E12 is the difference between javascript ref and spreadsheet ref.
Logger.log('Value in hours with offset correction : '+hours); // show result in hours (obtained by dividing by 3600000)
}
note : this code gets only hours , if your going to have minutes and/or seconds then it should be developped to handle that too... let us know if you need it.
EDIT : a word of explanation...
Spreadsheets use a reference date of 12/30/1899 while Javascript is using 01/01/1970, that means there is a difference of 25568 days between both references. All this assuming we use the same time zone in both systems. When we convert a date value in a spreadsheet to a javascript date object the GAS engine automatically adds the difference to keep consistency between dates.
In this case we don't want to know the real date of something but rather an absolute hours value, ie a "duration", so we need to remove the 25568 day offset. This is done using the getTime() method that returns milliseconds counted from the JS reference date, the only thing we have to know is the value in milliseconds of the spreadsheet reference date and substract this value from the actual date object. Then a bit of maths to get hours instead of milliseconds and we're done.
I know this seems a bit complicated and I'm not sure my attempt to explain will really clarify the question but it's always worth trying isn't it ?
Anyway the result is what we needed as long as (as stated in the comments) one adjust the offset value according to the time zone settings of the spreadsheet. It would of course be possible to let the script handle that automatically but it would have make the script more complex, not sure it's really necessary.
For simple spreadsheets you may be able to change your spreadsheet timezone to GMT without daylight saving and use this short conversion function:
function durationToSeconds(value) {
var timezoneName = SpreadsheetApp.getActive().getSpreadsheetTimeZone();
if (timezoneName != "Etc/GMT") {
throw new Error("Timezone must be GMT to handle time durations, found " + timezoneName);
}
return (Number(value) + 2209161600000) / 1000;
}
Eric Koleda's answer is in many ways more general. I wrote this while trying to understand how it handles the corner cases with the spreadsheet timezone, browser timezone and the timezone changes in 1900 in Alaska and Stockholm.
Make a cell somewhere with a duration value of "00:00:00". This cell will be used as a reference. Could be a hidden cell, or a cell in a different sheet with config values. E.g. as below:
then write a function with two parameters - 1) value you want to process, and 2) reference value of "00:00:00". E.g.:
function gethours(val, ref) {
let dv = new Date(val)
let dr = new Date(ref)
return (dv.getTime() - dr.getTime())/(1000*60*60)
}
Since whatever Sheets are doing with the Duration type is exactly the same for both, we can now convert them to Dates and subtract, which gives correct value. In the code example above I used .getTime() which gives number of milliseconds since Jan 1, 1970, ... .
If we tried to compute what is exactly happening to the value, and make corrections, code gets too complicated.
One caveat: if the number of hours is very large say 200,000:00:00 there is substantial fractional value showing up since days/years are not exactly 24hrs/365days (? speculating here). Specifically, 200000:00:00 gives 200,000.16 as a result.

format datetime specific timezone

I am using globalize to format datetime per locale.
var Globalize = require('globalize');
var formatter = Globalize('en-US').dateFormatter();
formatter(new Date());
It works great but I was wondering if I can format date for specific timezone. This way, it always formats date in the local machine timezone.
For example, let's say my machine timezone is PST. Can I use globalize to format date in EST?
Stolen from here
This solution works by using the getTimeOffset() (which returns the time difference between UTC time and local time, in minutes) function to find the UTC time offset of a given location and changing it to milliseconds, then performing calculations from UTC to return a time for a different time zone.
/**
* function to calculate local time
* in a different city
* given the city's UTC offset
*/
function calcTime(city, offset) {
// create Date object for current location
var d = new Date();
// convert to msec
// add local time zone offset
// get UTC time in msec
var utc = d.getTime() + (d.getTimezoneOffset() * 60000);
// create new Date object for different city
// using supplied offset
var nd = new Date(utc + (3600000*offset));
// return time as a string
return "The local time in " + city + " is " + nd.toLocaleString();
}
This solution will work, but it's simpler to express timezone in minutes and adjust the UTC minutes.
Please let me know if this works for you!
The javascript function new date() generates a date/time stamp based off the machine time at the moment that the function was called. So if the function is called by a machine that is in Alaska, it will generate a date/time stamp based on the current time in Alaska at that exact moment.
w3school.com has great references to most coding related items. You can find the answer to your question here.

How the .getTime() can preserve the original date dd/MM/yyyy?

I have a trouble. I have an angular Javascript application that is storing the dates in mysql with milliseconds, but in some moments the date is interpreted with one more or less day. For example:
If the user selects in the date picker: 03/02/2017, the application is saving this (in milliseconds) as 02/02/2017 or 04/02/2017. I believe it is due to the timezone. This is the way I'm using to convert the date in milliseconds:
var temp = $("#datetimeField").val().split("/");
var newDatetime = new Date(temp[2], temp[1] - 1, temp[0]).getTime();
As you can see, I know the day, the month and the year before store it in the database. Normally the date is stored and works well, but in some moment the date changes as I showed above. How can I always get temp[2]/temp[1]-1/temp[0] ??? from the stored milliseconds?

Comparing today's date with another date in moment is returning the wrong date, why?

I'm using moment.js 1.7.0 to try and compare today's date with another date but the diff function is saying they are 1 day apart for some reason.
code:
var releaseDate = moment("2012-09-25");
var now = moment(); //Today is 2012-09-25, same as releaseDate
console.log("RELEASE: " + releaseDate.format("YYYY-MM-DD"));
console.log("NOW: " + now.format("YYYY-MM-DD"));
console.log("DIFF: " + now.diff(releaseDate, 'days'));
console:
RELEASE: 2012-09-25
NOW: 2012-09-25
DIFF: 1
Ideas?
Based on the documentation (and brief testing), moment.js creates wrappers around date objects. The statement:
var now = moment();
creates a "moment" object that at its heart has a new Date object created as if by new Date(), so hours, minutes and seconds will be set to the current time.
The statement:
var releaseDate = moment("2012-09-25");
creates a moment object that at its heart has a new Date object created as if by new Date(2012, 8, 25) where the hours, minutes and seconds will all be set to zero for the local time zone.
moment.diff returns a value based on a the rounded difference in ms between the two dates. To see the full value, pass true as the third parameter:
now.diff(releaseDate, 'days', true)
------------------------------^
So it will depend on the time of day when the code is run and the local time zone whether now.diff(releaseDate, 'days') is zero or one, even when run on the same local date.
If you want to compare just dates, then use:
var now = moment().startOf('day');
which will set the time to 00:00:00 in the local time zone.
RobG's answer is correct for the question, so this answer is just for those searching how to compare dates in momentjs.
I attempted to use startOf('day') like mentioned above:
var compare = moment(dateA).startOf('day') === moment(dateB).startOf('day');
This did not work for me.
I had to use isSame:
var compare = moment(dateA).isSame(dateB, 'day');

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