Validate Date FORMAT (not date string) using MomentJS? - validation

I've seen that you can use an ".isValid()" function to check that a given string is in a date format:
moment('2007-05-05', 'YYYY-MM-DD', true).isValid()
But is there a way to confirm that the format is correct? For example:
'YYYY-MM-DD' should return true, but
'YYYY-MM-DDsadsadl' should return false since the characters at the end of the string aren't valid DateTime chars.
We're working on a tool that allows a user to input an existing date format, and then a second input to enter the desired format, but we need validation to ensure the string can properly parse and convert, but they aren't entering a specific date.
The application must accept any and all possible date formats.

Use the following function to validate your format.
validFormat = function(inputFormat){
var validation = moment(moment('2017-06-17').format(inputFormat), inputFormat).inspect();
if(validation.indexOf('invalid') < 0)
return true;
else
return false;
}
Do spend some time to understand this. This simply does a reverse verification using inspect(). The date 2017-06-17 can be replaced by any valid date.
This Moment Js Docs will help you identify the valid formats.
Just make a call to this function as
validFormat('YYYY MM DD')

const getIsValid = inputFormat => moment(moment().format(inputFormat), inputFormat).isValid()
Explanation:
moment().format(inputFormat) - Create a date string from the current time from that format
This is then wrapped with moment() to make that string a moment date object, defining the format to parse it with. Finally we call the isValid() property on that moment date object. This ensures we are able to both create and parse a moment with our custom format.

Related

How to convert yyyy-mm-ddThh:mm:ss [+-] hh:mm to timestamp yyyy-mm-dd hh:mm:ss in Datastge?

How to convert yyyy-mm-ddThh:mm:ss [+-] hh:mm to timestamp yyyy-mm-dd hh:mm:ss in Datastge?
Eg:
From
2021-01-26T01:07:00-05:00
To
2021-01-26 01:07:00
Depending on the original data type you could use string functions
and StringToTimestamp
Otherwise you could check out Date and Time functions as well.
If the data type is string, convert the "T" to a space " " using Convert() function.
Use Left() function to get rid of the "+/- hh:mm".
If the data type is timestamp, do nothing until you need to display it; the internal representation of a timestamp does not have a "T" in it. If you're writing it to a text file, for example, use TimestampToString() function to specify your desired format, although the default format may well suit your need.

Forcing Java 8 LocalTime toString to report omitted values

I have the following datetime helper method that converts a UTC-zoned Java 8 Date into a datetime string:
public static String dateTimeString(Date date) {
return date.toInstant().atZone(ZoneId.of("UTC")).toLocalDateTime().toString();
}
The desired result is to always have the resultant String be formatted as:
YYYY-MM-dd'T'HH:mm:ss'Z'
Problem is, Java 8 LocalTime#toString() intentionally strips off time components that are zero. So for instance if I have a Date instance that represents June 8, 2018 at 12:35:00 UTC. Then the output of this method above is: 2018-06-08'T'12:35'Z'. Whereas I want it to contain any zeroed-out second/minute/hour components (e.g. 2018-06-08'T'12:35:00'Z').
Any ideas?
private static DateTimeFormatter formatter = DateTimeFormatter.ofPattern("uuuu-MM-dd'T'HH:mm:ssX");
public static String dateTimeString(Date date) {
return date.toInstant().atOffset(ZoneOffset.UTC).format(formatter);
}
Just use a fixed format pattern string to get your desired format. Let’s try it:
System.out.println(dateTimeString(new Date(0)));
System.out.println(dateTimeString(new Date(1_524_560_255_555L)));
This prints:
1970-01-01T00:00:00Z
2018-04-24T08:57:35Z
In the first example hours, minutes and seconds are printed even if they are 0.
In the second example milliseoncds are omitted even when they are non-zero (you see that the milliseconds value I specified ends in 555).
All of this said, the output conforms to the ISO 8601 format no matter if you have 2018-06-08T12:35Z, 2018-06-08T12:35:00Z or even 2018-06-08T12:35:00.000000000Z. So you may want to check once more whether leaving out the second works for your purpose before you take the trouble of defining your own formatter.
Link: Wikipedia article: ISO 8601
I don't see why you portray the default output to have its letters enclosed in single quotes when Java's actual output instead looks like 2018-06-08T12:35Z, but anyway, here's the code that produces it as desired, with no omissions:
final LocalDateTime ldt = LocalDateTime.of(2018, 6, 8, 12, 35, 0);
final ZonedDateTime zdt = ZonedDateTime.of(ldt, ZoneId.of("Z"));
final DateTimeFormatter dtf = DateTimeFormatter.ofPattern("yyyy-MM-dd'''T'''HH:mm:ss''X''", Locale.US);
System.err.println(dtf.format(zdt));
Output:
2018-06-08'T'12:35:00'Z'
Personally, I'd probably prefer a format like this, containing the millis, giving time zone information not requiring additional knowledge from the user, and not having imho superfluous characters:
FORMAT: "yyyy-MM-dd HH:mm:ss'.'SSS Z"
OUTPUT: 2018-06-08 12:35:12.345 +0200
It appears that there is no out of the box solution. The simplest way would be to write your own class that extends DateTimeFormatter and override method public String format(TemporalAccessor temporal) where you would call the original method and then if needed modify the output String. See the flags 'Z' for formatter. If that flag is present then you will need to modify the original output.

Correct strptime format for Input Type Time on Rails 4

Want to use the
<input name=attendance[something] type="time">
For time input. However cant make it seem to match with a Datetime object; for manipulation before insertion to ActiveRecord
myTimeIn = Time.strptime(params[attendance][something],"%H:%M")
keeps getting
invalid strptime format - `%H:%M'
What is the correct format for a input type=time field?
Looks like the value of params[attendance][something] may be blank or not of the correct format. You could do something like below to avoid the error:
t = params[attendance][something]
myTimeIn = Time.strptime(t,"%H:%M") if t =~ /\d{1,2}:\d{2}/
As per this HTML example, the value produced by <input/> of type time is HH:MM

Java8 LocalDateTime to XMLGregorianCalender Remove "+05:30" Portion

Did like below,
LocalDateTime currentUTCTime = LocalDateTime.now(ZoneId.of("UTC"));
String reqPattern = currentUTCTime.format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss:SSS"));
System.out.println("Required pattern: " + reqPattern);
GregorianCalendar calendar = GregorianCalendar.from(currentUTCTime.atZone(ZoneId.systemDefault()));
XMLGregorianCalendar xcal = DatatypeFactory.newInstance().newXMLGregorianCalendar(calendar);
System.out.println("But Showing As :" + xcal);
I want the output as 2015-06-18 11:59:15:135, but when i set the xcal to
a XML tag which takes XMLGregorianCalender, it shows like 2015-06-18T11:59:15.135+05:30.
How can i remove the +05:30 portion?
Use this code:
LocalDateTime currentUTCTime = LocalDateTime.now(); // using system timezone
String iso = currentUTCTime.toString();
if (currentUTCTime.getSecond() == 0 && currentUTCTime.getNano() == 0) {
iso += ":00"; // necessary hack because the second part is not optional in XML
}
XMLGregorianCalendar xml =
DatatypeFactory.newInstance().newXMLGregorianCalendar(iso‌​);
Explanation:
The code makes use of the given factory method expecting a lexicographical representation of a local timestamp in ISO-8601-format. And since a LocalDateTime does not refer to any timezone, its output via toString() cannot contain a timezone offset. Result: XMLGregorianCalendar considers the timezone offset as "not set".
Correction:
The original code did not especially bother about the ISO-variant of formatted output of currentUTCTime.toString(). However, the java.time-API produces an output without seconds or nanoseconds if those parts are equal to zero. This is perfectly legal in ISO, but the W3C-consortium has made the second part non-optional. And the class XMLGregorianCalendar closely follows this deviating spec. Therefore the shown hack above using simple string concatenation in this special edge case. Thanks a lot to #Dave's comment. By the way, using currentUTCTime.format(DateTimeFormatter.ISO_DATE_TIME) as suggested in this comment is also possible (instead of the shown hack).

Time scale won't convert dates to numbers

I am having trouble with using the time scale. I have dates in the format 'YYYYMMDD', I parse these with:
parseDate = d3.time.format("%Y%m%d").parse
I set the domain to static dates using the same above function. I can see the dates in correct format in the console. But when applying the scale function x, it returns 'NaN' WAT?
It's probably something small I'm not seeing, it's driving me mad...
Code can be found here: http://bl.ocks.org/pberden/5668581
I think the problem is in the way you call d3.nest. According to the spec
The key function will be invoked for each element in the input array, and must return a string identifier that is used to assign the element to its group.
You convert the Day in your csv file to a Date but then, as you are building a map from the array using d3.nest(), the invocation of the key function turns this Date to a String by doing an implicit conversion.
To fix this I think you could try to force your line generator to turn a String into Date like so
var line = d3.svg.line()
.x(function(d) { return x(new Date(d.key)); })
.y(function(d) { return y(d.values.Value); });

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