Moment.js internal object what is "_d" vs "_i" - momentjs

I am using Moment.js and manipulating a date using moment.hour(xx) moment.minute(xx).
When i console.log the moment i see that the object contains a _d and _i:
the _d contains the correct changed moment.hour() or moment.minute() changes however the _i object contains the original?
k {_isAMomentObject: true, _i: Thu Dec 11 2014 20:34:00 GMT+0200 (South Africa Standard Time), _isUTC: false, _pf: Object, _locale: j…}
_d: Thu Dec 11 2014 14:00:00 GMT+0200
_i: Thu Dec 11 2014 20:34:00 GMT+0200
Could anyone enlighten me?

Pay no attention to those. Use the various output functions, such as .format() instead. See the Moment.js guidance on this topic. In short, all fields that are prefixed with an underscore (_) should be considered off limits.
The moment internals have some quirks due to how the Date object works. All of the functions in the public API take them into account, but you probably don't want to figure them out yourself.
Just to be complete though, I'll elaborate on their purpose:
_i is the input used when create the moment object. It can be a string, a number, an array, or a Date object.
However, if another moment object is passed in, the _i will be copied to that moments _i, and other properties will also be copied over. _i will never be a moment object.
_i can also be undefined, in the case of creating the current moment with moment().
_d is the instance of the Date object that backs the moment object.
If you are in "local mode", then _d will have the same local date and time as the moment object exhibits with the public API. The timestamps returned by getTime or valueOf will also match.
If you are in "UTC mode", then _d will still have the same UTC date and time as the moment object exhibits with the public API. This may be confusing, as you'd need to look at getUTCDate and other UTC-based functions on _d in order to see them match. The timestamps will still match here as well.
If you've changed the time zone offset, with the utcOffset, zone, or tz functions, then the _d value cannot stand alone. It must also consider if _offset is defined. If it is, then the timestamp backing the _d object has to first be adjusted by the amount of the offset. You can see this behavior in the implementation of the valueOf method here.
Also, if you look at the string output of _d when a different offset or time zone has been applied, it will appear that _d is using the local time zone. However, that conversion to local time is simply a side effect of the toString function of the Date object. Moment does not use that result in its functions.
This is the behavior for these two fields as of the current version (2.10.6 as I'm writing this). However, there are other fields as well, and since these are internal fields, it's entirely possible the behavior could change in a future version. In particular, see issue #2616.

As a complement to #Matt's answer:
Checkout this result from the chrome's console:
date1 is a moment's valid object:
As you can see, ._d and ._i have different values. So you better use the format() function (as #Matt Johnson wrote) inside your source code.

Related

Moment return the same value passed to it instead of utc value

Im trying to trasform a date to utc but moment return the same value i use.
for example
moment(date, 'YYYY-MM-DD HH:mm:ss').utc().format('YYYY-MM-DD HH:mm:ss')
if i use date = '2022-01-07 11:30:00' moment return 2022-01-07 11:30:00
do i have to set the timezone of the value first? why moment return the wrong value? it should return +3 hours that date.
You'll need to define the timezone in which the date is, then the offset will be as expected:
Example, using Europe/Amsterdam as timezone
const date = '2022-01-07 11:30:00';
const utc = moment(date, 'YYYY-MM-DD HH:mm:ss')
.tz('Europe/Amsterdam')
.utc()
.format('YYYY-MM-DD HH:mm:ss');
console.log(utc);
<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.29.1/moment.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/moment-timezone/0.5.32/moment-timezone-with-data.min.js"></script>
This will output 2022-01-07 10:30:00 since Amsterdam time is -1 compared to UTC.
Small side node, quoting MomentJS Project Status page
We now generally consider Moment to be a legacy project in maintenance mode. It is not dead, but it is indeed done.
In practice, this means:
We will not be adding new features or capabilities.
We will not be changing Moment's API to be immutable.
We will not be addressing tree shaking or bundle size issues.
We will not be making any major changes (no version 3).
We may choose to not fix bugs or behavioral quirks, especially if they are long-standing known issues.
The data you pass in doesn't have any indication of the timezone it's in, so moment is (I believe) assuming it's in utc already.
In related news, look into using the date-fns library instead of moment. Moment is getting old...
Moment github
Moment.js is a legacy project, now in maintenance mode. In most cases,
you should choose a different library.
This returns the same date since you never indicated any timezone
var time = moment("2013-08-26 16:55:00") //this creates time in my tz
You can set a timezone like this:
var time = moment("2013-08-26 16:55:00").tz("America/Los_Angeles");

moment.format() returns next day

So Im using Fullcalendar and on dayClick I'm trying to find events that match the day clicked.
var events = $calendar.fullCalendar('clientEvents');
if(events.length > 0) {
for (var i = 0; i < events.length; i++) {
if (date.format('YYYY-MM-DD') == events[i].start.format('YYYY-MM-DD')) {
...
Now
date.format('YYYY-MM-DD')
returns the day I clicked but when the for loop gets to that days events then
events[i].start.format('YYYY-MM-DD')
returns the next day. This seems to be affected by UTC but this applies to ALL days with events. Not just today. I've tried different formats and still the same. Here's something I noticed though:
n
_ambigTime:false
_ambigZone:true
_d:Thu Feb 09 2017 08:00:00 GMT-0500 (EST)
_f:"YYYY-MM-DD HH:mm:ss"
_fullCalendar:true
_i:"2017-02-08 13:00:00"
_isAMomentObject:true
_isUTC:true
_isValid:true
_locale:f
Notice that _d and _i are different. _i is actually the right date/time. So how can I reference that?
All moment properties starting with _ (like _d and _i) are for internal use and should not be used.
If you want to check if two moment object represent the same day you can use isSame passing the second parameter to limit granularity, instead of comparing formatted strings. In your case:
date.isSame(events[i].start, 'day')
The problem is that some of your objects are created in UTC mode (_isUTC: true), so they will be displayed using UTC time (previous day in some cases) instead of local time.
More info about UTC mode here:
By default, moment parses and displays in local time.
If you want to parse or display a moment in UTC, you can use moment.utc() instead of moment().
This brings us to an interesting feature of Moment.js. UTC mode.
While in UTC mode, all display methods will display in UTC time instead of local time.

System.DateTime comparison ('>') or ('<') does not give what I expected

I want to get files from a list for all the files whose filedate > today's cutOff - so, I have the following codelet
string[] MyFiles = Directory.GetFiles(MyConfig.pathTransmittedFiles, "*.adf")
.Where(file => new FileInfo(file).LastWriteTime > dtCutOff).ToArray();
I have a file whose LastWriteTime is "{11/3/2015 1:33:26 PM}" being picked up by my collection with dtCutOff == "{11/3/2015 1:33:26 PM}"! So '>' didn't seem to work.
First, I would try running it without the Where clause, just to make sure that all files you expect are indeed part of the initial array returned from Directory.GetFiles. It's entirely possible that date/time comparison is not the source of the discrepancy. It may be more related to the issue Ivan linked to in the question comments, or it may be permission related, or some other thing.
Next, be aware that DateTime violates SRP in that it has a Kind property, which is one of the three DateTimeKind enumeration values. It's either Local, Utc, or Unspecified.
In the case of DateTime.Now, the Kind will be DateTimeKind.Local. File.GetLastWriteTime also returns its value with local kind. Therfore, if you always derive your dtCutOff from DateTime.Now in the manner you showed in the question, then it will almost always be the correct comparison function.
The "almost" stems from the fact that DateTimeKind.Local can actually represent two different kinds under the covers. In other words, there are actually four kinds, but two of them are exposed by one. This is described as "DateTime's Deep Dark Secret" in Jon Skeet's blog post More Fun with DateTime, and is also mentioned in the comments in the .NET Framework Reference Source. In practice, you should only encounter this in the ambiguous hour during a fall-back daylight saving time transition (such as just occurred last Sunday 2015-11-01 in the US).
Now, to the more likely case that your dtCutOff is actually derived not from DateTime.Now, but rather from user input or database lookup or some other mechanism, then its possible that it actually represents the local time in some other time zone than the one on your local computer. In other words, if the dtCutOff has a Kind of DateTimeKind.Utc, then the value is in terms of UTC. If it has a Kind of DateTimeKind.Unspecified, then the value might be in terms of UTC, or the local time zone, or some other time zone entirely.
Here's the kicker: Comparison of two DateTime values only evaluates the value underlying the Ticks property. It does not consider Kind.
Since file times are absolute points in universal time (on NTFS anyway), then you really should use the File.GetLastWriteTimeUtc method, rather than the methods that work in local time.
There are two approaches you could use:
Load the modified property as UTC, using:
myResult.modified = File.GetLastWriteTimeUtc(myFile);
Populate dtOffset appropriately.
If you're loading from the current time, then use DateTime.UtcNow.
If you're loading from other input, ensure the value is converted to UTC to match the input scenario. For example, use .ToUniversalTime() if the value is in terms of the local time zone, or use the conversion functions in the TimeZoneInfo class if the value is in another time zone.
OR
Change your modified property to be a DateTimeOffset instead of a DateTime.
Load that using:
myResult.modified = new DateTimeOffset(File.GetLastWriteTimeUtc(myFile));
Define dtCutOff as a DateTimeOffset, and populate appropriately.
If you're loading from the current time, then use DateTimeOffset.UtcNow.
If you're loading from other input, ensure the offset is set to match the input scenario. Use TimeZoneInfo functions if you need to convert from another time zone.
DateTimeOffset has many advantages over DateTime, such as not violating SRP. It's always representing an absolute moment in time. In this scenario, it helps to know that comparison operators on DateTimeOffset always reflect that absolute moment. (In other words, it internally adjusts to UTC before doing the comparison.)
This code works:
var cutffDate = new DateTime(2015,1,1); // or whatever
var allFiles = Directory.GetFiles(MyConfig.pathTransmittedFiles, "*.adf");
var datedFiles = allFiles.Where(f => (new FileInfo(f)).LastWriteTime > cutffDate);
Update:
Since your issue seems to be a precision-related one you could change the comparison to:
const long precision = 10; // vary this as needed
allFiles.Where(f =>
(new FileInfo(f)).LastWriteTime.ToFileTime()/precision > cutffDate.ToFileTime()/precision);
Alternatively you could use ...LastAccessTime.Ticks/TimeSpan.TicksPerMillisecond
In addition to that you may need to convert all DateTime values to UTC (LastAccessTimeUtc and DateTime.UtcNow) to make sure it's not some weird timezone issue
Since the files were fed into the queue once a day so the scale of precision is not required down to a millisecond or something. So that one-second TimeSpan difference is acceptable to do the trick and make my case work.
string[] MyFiles = Directory.GetFiles(MyConfig.pathTransmittedFiles, "*.adf")
.Where(file => new FileInfo(file).LastWriteTime - TimeSpan.FromSeconds(1) > dtCutOff)
.ToArray();
Now my file with modified date "{11/3/2015 1:33:26 PM}" didn't go into my collection when my cutOffDate is "{11/3/2015 1:33:26 PM}" while my other file with modified date "{11/3/2015 1:33:27 PM}" have successfully passed into my collection as expected!! So, it works and that's how it should work after all these advises! Thanks ye-all.
Looks like your Where clause lambda might be incorrect. Try this.
string[] MyFiles = Directory.GetFiles(MyConfig.pathTransmittedFiles, "*.adf").Where(file => file.modified > dtCutOff).ToArray();

How to handle Edm:DateTime form OData interface in SAPUI5 correct?

Is there a definition what values should be send in OData Edm:DateTime of a SAP Netweaver Gateway service?
Especially should it always be interpreted as UTC?
I assume the SAPUI5 library is smart enough to handle all this time zone problems automatically if the interface is correct defined -- question is, what is correct?
I would prefer to use some code like this, at client side:
new sap.m.DatePicker({
value : {
path : "BirthDate",
type : new sap.ui.model.type.Date
}
}),
How do you solve these problems?
Edit
Time zone handling seems still to be strange to me.
SAP Gateway Server sends in an Edm:DateTime following: 2015-04-16T00:00:00
Any time zone information is missing.
If I bind a date picker like this:
var oContent = new sap.m.DatePicker({
value : {
path : "Date",
type : new sap.ui.model.type.Date({
style: "short",
})
}
})
I got the following output: 16.04.15 (seems to be correct).
Binding a date picker without type information shows: Thu Apr 16 2015 02:00:00 GMT+0200 (Mitteleuropäische Sommerzeit)
If I change the date with the date picker to 17.04.15 the second line is:
Fri Apr 17 2015 00:00:00 GMT+0200 (Mitteleuropäische Sommerzeit)
Please note the difference in time (2 hours missing).
If I send it to the server I got Edm.DateTime == 2015-04-16T00:00:00
Control shows:
Thu Apr 16 2015 02:00:00 GMT+0200 (Mitteleuropäische Sommerzeit)
If I use
new sap.m.DatePicker({
value : {
path : "Date",
type : new sap.ui.model.type.Date({
style: "short",
UTC: true
})
}
})
Data seems to be correct (the 2 hours are not missing after picking a new date).
I am asking me, is there any definition what type of data gateway will send?
If the timezone is missing inside the Edm.DateTime information how should a client work correct? Especially if clients are in different time zones available?
Strange enough I have a similar problem by using a filter. But there the UTC flag seems not working.
Anyone with some experience on that topic? Or any hints to a good documentation?
* https://sapui5.netweaver.ondemand.com/sdk/#docs/guide/91f3070d6f4d1014b6dd926db0e91070.html
Says more or less "take care" but not how :-/
Further information
I detected the same question on SAP network (http://scn.sap.com/thread/3574419). Not sure if the given answer is correct. Looks like hacking around in meta-data which should not be required?
I am still searching for a solution to this problem
I detected different handling of data in case of binding and filter usage.
I can't answer with regard to SAP, as I am not familiar. But I can provide some insights based on OData.
The Edm:DateTime type is based on the W3C XML Schema xs:dateTime, which is in-turn based on ISO8601. Both XML Schema and ISO8601 state that times without a time zone are to be considered "local time". That is, local to someone. Whose "local" it is intentionally undefined.
From W3C XML Schema §3.2.7:
"Local" or untimezoned times are presumed to be the time in the timezone of some unspecified locality as prescribed by the appropriate legal authority
From ISO 8601 3rd Edition §4.3.2:
The zone designator is empty if use is made of local time ...
Consider your example of 2015-04-16T00:00:00. The only way to know what exact moment in time this refers to is to have some additional context applied. In the case of a birthday, this could be the time zone where the person is currently located (where they celebrate their birthday, not where they are born). Or, it could be some arbitrary location if the person's location is unknown - perhaps the time zone of the person using the system.
Therefore, the interpretation of the value is where the time zone is being applied. In your case, it would appear that some local time zone is being applied during deserialization.
Also consider that a birthday is better represented by just a calendar date, rather than midnight on a date. The Edm:Date type is better suited for this. For other types, especially if you know that the value is UTC or in a specific time zone, then Edm:DateTimeOffset is more appropriate.
Also recognize that the Edm:DateTime type was dropped from OData spec in version 4.0. Many (including myself) consider this a mistake. I'm not sure if this affects you or not, but you should be aware.
Hope that helps.
Use type sap.ui.model.type.Date({ oFormatOptions:{ style: "short", UTC: true} }) this will retain your date as it is sent by server
Could you try binding the date path to dateValue instead of value.
It should automatically interpret Edm:DateTime.
new sap.m.DatePicker({
dateValue : "{BirthDate}"
})

DateTime changes by Breeze before save changes

I am creating a new Entity and inside constructor I set the datetime like
function Project() {
this.created = moment().format();
}
which produce a result in console the current date and time
Sat Jun 07 2014 18:48:41 GMT+0500 (Pakistan Standard Time)
As soon as I call save changes and see the posted date in the network tabe it changes the hour part of datetime 2014-06-07T13:48:41.000Z
It looks like Breeze does this, may be I am wrong, Any suggestion how can I prevent this to happen?
Breeze is just serializing the date for transport It is not transformed at all. If you look it is 5 hours different in UTC meaning it will localize out the same when you moment.format it again.
If you want to re-localize it just use moment(yourDate).format(LL) or something similar.
http://momentjs.com/ and go to Internationalization section

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