[Feauture] Support string arguments to utcOffset method

[ognjenjevremovic]

✅ Closes: #1085

↪️ Pull Request

• Extend utcOffset method with support for string argument representing the offset.
• Provide the unit test(s) for the code change.

Code example

Allow UTC offset to be defined as a string. Valid formats are:

• +HH:mm,
• -HH:mm,
• +HHmm
• -HHmm

Example usage:

dayjs().utcOffset(`+08:00`, true)

✔️ PR Todo

• Added/updated unit tests for this change
• Included links to related issues/PRs.

📝 Additional notes

After the change I ensured that:

• all tests are passing, by running npm run test && npm run test-tz,
• formating / code style is consistent, by running npm run lint*.

There are 2 failing unit tests present on the dev branch and as such are present in this fix as well, however they are not affected by this issue / code introduced.

[iamkun]

can we skip these three lines, and put everything to REGEX_OFFSET_HOURS_MINUTES_FORMAT regex?

[ognjenjevremovic]

I am not sure I understood you well.
Can you provide more info on the changes you would like regarding this code block?

Do you want the empty line removed and have the offsetFromString method just below the REGEX_OFFSET_HOURS_MINUTES_FORMAT, with no blank space in between?

[iamkun]

it seems REGEX_VALID_OFFSET_FORMAT and REGEX_OFFSET_HOURS_MINUTES_FORMAT is doing the same thing?

[ognjenjevremovic]

Hey @iamkun the two provided regexes have some slight differences, but serve different purposes.

REGEX_VALID_OFFSET_FORMAT is used to test the provided string value format.
If the method argument is not prefixed with - or + symbol the method exists early with null value. That's the only purpose of this regex.

REGEX_OFFSET_HOURS_MINUTES_FORMAT is used to split the output of the first regex into symbol, hours, minutes variables. We need to split the string in order to provide the necessary calculations.
This could've been perhaps achieved using the String.prototype.slice method instead, but would require multiple calls (3 calls to be precise in order to extract symbol, hours and minutes values) - regex might be faster in this case.

We could merge these two together but the method logic should be updated to reflect this change. It would break SR principle (more of a personal preference) and might be more error prone.
I am able to provide the requested changes, just wanted to give you a brief overview of the design choices behind 2 regex pattern 🙂 .

[iamkun]

that make sense, thanks

[iamkun]

🎉 This PR is included in version 1.10.5 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

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