Javascript Date acting weird - javascript

Okay, I have heard about it but I can confirm now that the Javascript Date functionality is a disaster zone. And I have created a monster out of it. I have this Program :
A JSON object contains list of holiday dates and its respective label.
I need to find out the date of 5 business days from today (excluding saturday, sunday and holiday if any which is contained in the JSON object.) Good stuff so far. Then this 5 business days' date is going to be devoured by the jquery calender as a default selected date which is not included in the fiddle as it is irrelevant. (Note: the start date on the calender is tommorow's date) Good stuff again. THEN, comes this part: If it is before noon today, I can select tommorow else start date is day after tommorow. I'm elaborating this because it is included in this fiddle.
So the problem is multiple initialization of the function which handles above functionality is not producing consistent result. It was calculating 5 business days on my system, but when i made this fiddle, it is calculating 4. The date of "5th" business days is incremental by 1 on each call.
http://jsfiddle.net/xXQ7j/27/
Anyone!

Your problem is probably caused by timezone issues.
Whenever possible you should use new Date(y, m, d) to create a date object, rather than supplying a string. In particular, I've found that you get a date relative to 00:00 UTC if you specify a string in format yyyy-mm-dd but one relative to local midnight if you use yyyy/mm/dd.
In any event, I would suggest a different approach:
convert your holiday date into an object, with the date being the key
generate today's date
if it's after noon, get tomorrow's date - d.setDate(d.getDate() + 1)
create an empty array
add one day (per #3 above)
check if the new day is Saturday or Sunday, if so, go back to #5
check if the new day is in the holiday list, if so, go back to #5
add the new date to the array
repeat until you have 10 entries
That should give you the next 10 business days in your array. Pick the ones you need to fill out your date picker.

Related

Convert relative time to datetime in Javascript

How can I convert a relative date/time string to a real date/time in Javascript (can use libraries)
For example, the user will input into an edit field any of the following examples (among others):
THIS IS THE INPUT:
2 weeks ago
Last 3 weeks
24 hours ago
Last 4 months
Last week
Last monday
So, taking now/todays datetime as a starting point, I need to get the date/time they are referring to.
So is today is 2018-04-06 11:19 and they enter '1 week ago' or 'a week ago' then I need a routine which will return
'2018-03-30 11:19'
as the OUTPUT
I know about moment.js and how to use that to change a date/time/moment to a relative datetime, but I need it done the other way around, - to change a relative date string to a date/time.
EDIT:
I have now found :
- https://github.com/wanasit/chrono
which seems to solve the problem.
https://github.com/wanasit/chrono This library seems to provide exactly as was requested in the OP. The input is a relative date in Natural Language (almost) and the output is a date.

Comparing 2 dates with momentJS

I am trying to compare a DAY/TIME e.g. Monday 09:00:00 with the current time to see if I am past that point in the week. e.g. If it is now 05:00:00 on Monday it should return true however it is returning false everytime
var dayTime = Moment("Wednesday 17:00:00", "dddd HH:mm:ss");
var now = Moment(Moment.now(), "dddd HH:mm:ss");
console.log(Moment.utc(dayTime).isBefore(now)); //returns false all the time
I found the following similar questions but it didn't seem to fix the issue after formatting the time.
Comparing two times with Moment JS
When I replace the moment.now() with a string such as "Wednesday 17:00:00" it returns the expected result.
Any idea what I need to do to moment.now() in order for this to work correctly?
Moment.now can be used as an extension point, but it's really not a public API. To get the current time in momentjs you just call moment(). Note that all moment calls use lowercase moment.
To see if your date and time is before the current time, you would just call:
moment('01/01/2016', 'MM/DD/YYYY').isBefore(moment())
You would replace the date and format in question with your own.
I see that you have a date format that includes only day of week and time. Moment will parse this, but be aware that the behavior might not be what you expect. When I parse your date, I get Wednesday December 30, 2015. Exactly what day this lands on will vary by locale. In any case, I doubt that it is what you want. If at all possible, I would get year, month, and day.
If you would like to instead set the moment to Wednesday this week, set the day on the moment using .day(). For instance:
moment().day(3).format()
"2016-06-15T20:19:55-05:00"
For anyone who is interested, the code I posted in my question was changing the day/hour but was setting the year to 2015 which meant that it was always in the past.
To fix I separated out the Day and the Hour and set to moment. Then compared that with now. e.g.
moment().set({"Day": "Friday", "Hour": "17"}).isBefore(moment())

Moment Js Issue : isoWeekYear & isoWeek method behavior

I fetched the iso week from a date by using moment's isoWeek function.
moment(new Date(2015,11,28)).isoWeek() //output 53
I fetched the iso week year from the same date by using moment's isoWeekYear function.
moment(new Date(2015,11,28)).isoWeekYear() //output 2015
But when I gave the same outputs to the input of moment function it results a different date.
moment().isoWeek(53).isoWeekYear(2015).isoWeekday(0).toDate() //output Dec 28 2014
For other dates it is working correctly. Is there anything that I am missing in my code or it is a bug with Moment ?
here is a demo JSFiddle console.log("Iso Week :",moment(new Date(2015,11,28)).isoWeek());
console.log("Iso Year :",moment(new Date(2015,11,28)).isoWeekYear());
console.log("Date :", moment().isoWeek(53).isoWeekYear(2015).isoWeekday(0).toDate());
It might be the order you've given to the segments.
This works:
moment().isoWeekYear(2015).isoWeekday(1).isoWeek(53).toDate());
Check this out from Moment.js docs.
if you chain multiple actions to construct a date, you should start
from a year, then a month, then a day etc. Otherwise you may get
unexpected results, like when day=31 and current month has only 30
days (the same applies to native JavaScript Date manipulation), the
returned date will be 1st of the following month.
Also isoWeekDays go from 1 to 7. By setting 0 you were getting next week's Monday.
first you have to understand one thing.in your first operation whats happening here is,
moment(new Date(2015,11,28)).isoWeek() //output 53
while creating date using new Date() you have passed 11 as month.so what will happen is while creating date month will get incremented by 1.so the date will be 2015-12-28.so the week number is 53.
so for the 3rd operation you have passed the same result.so moment returned the correct date.
in your case if you want to pass month subtract that by 1 in your 1st operation.
moment(new Date(2015,10,28)).isoWeek();
now you will get the correct answer

JavaScript setting dates in textboxes not consistent

I have a couple of textboxes where a user set a from date and to date from a button click which adds 7 days or substracts 7 to whatever is the current value in each box.
When the page is first loaded the dates that are added into the textboxes are based upon the user belonging to a group. Thus if a user belongs to group A, the from date is a Sunday, but if the user belongs to group B it is a Friday. This logic I set in the page load event in my ASP.Net page.
The situation that is baffling me, is whilst I can set the dates, and get my JavaScript to work with group A, if a switch the user to group B, and click on a button rather expecting the date in from changing from 17th January 10th January, it jumps to 29th December 2014. It seems to be getting a completely differently value initially 5th January 2015.
The JavaScript I have is:
var fromDateIn = new Date(formatDate(document.getElementById('<%=txtFromDate.ClientID%>').value));
var newfromdate = new Date(fromDateIn);
In one of the button event, I have:
function setNewFromDate() {
newfromdate.setDate(newfromdate.getDate() - 7);
document.getElementById('<%= txtFromDate.ClientID%>').value = formatDate(newfromdate);
var toDate = new Date(newfromdate);
document.getElementById('<%= txtToDate.ClientID%>').value = formatDate(toDate.setDate(toDate.getDate() + 6));
}
As I say, everything works perfectly and I get the right dates when the user is one group, but as soon I change the user to another group and set the initial from and to dates, I get this problem. Can anyone please advise I can get consistency in this?
Thanks
There is a problem with the way you are instantiating fromDateIn. You are passing it a value in the format dd/MM/yyyy, but the date constructor that takes a single string value is locale dependent and is treating the input as MM/dd/yyyy. This results in a completely bogus value for fromDateIn that throws everything else off.
You should find a way to determine the year, month and day for the start date (either by parsing it out of the textbox value or having the ASPX logic stuff it into the page somehow). And instantiate the date using the new Date(year, month, day) constructor. (This requires bearing in mind that month is 0-based [i.e. January = 0, February = 1]).
This line:
newfromdate.setDate(newfromdate.getDate() - 7)
Looks like you're trying to move back a week. This will fail. setDate changes only the Day of Month. Can you guess what happens when Day of Month is less than 7?

how to validate and add date using jquery

I am working on a health website.
I am having a field called Last Menstrual Period, its a textbox which has to be filled in by doctor in format of YYYY-MM-DD.
What I want to do is, I have to add 281 days into the LMP date that the doctor will be entering in order to generate the Expected Delivery Date (Child Birth)
So I need followings thing to do:
The date entered should be in format of YYYY-MM-DD
It should be a valid date i.e. taking care of leap years and invalid dates like 2013-02-31 etc.
After generating the Expected Date of delivery (based on LMP that is entered), it should be displayed on screen.
As soon as the date is entered in the LMP textbox, these validations should be performed and the Expected Date Of Delivery is displayed inside a tag below the LMP textbox
How can I do that? Here is what I have tried so far.
// Calculate Expected Date Of Delivery
$('#lmp_date').change(function()
{
var lmp_entered = $this.val();
if(lmp_entered)
{
// $('#edd').html('1');
}
else
{
// $('#edd').html('Please enter last menstrual date to calculate EDD');
Please help me how to implement these validations and display the date using jquery. I am a newbie in jquery so dont know much about it. Any small help will be highly appreciated.
for validation I don t recommend using another library especially for such a simple rule. if the rule is so strict just write your own and use it site wide.
For example block non-numberic entries to textbox and add dash "-" by your code in every 5th and 9th chars.
Then to validate check the length of text and dashed, use split to get year. month and day separately and convert it to date with Date(txtYear,txtMonth,txtDay) if your date's year, month and day are equals to your txtYear, Month and Day then it means it s a valid date. After that use the below to calculate birth date.
just use Date constructor like below
var delDate = new Date(year, month, day + 281)
Just don t forget months start 0 in JS so Jan = 0, Feb = 1 etc.

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