Colon in timezone

[thernstig]

According to https://en.wikipedia.org/wiki/ISO_8601 the timezone is recommended to contain a colon.

Representations can be done in one of two formats – a basic format with a minimal number of separators or an extended format with separators added to enhance human readability.[14][15] The standard notes that "The basic format should be avoided in plain text."[16] The separator used between date values (year, month, week, and day) is the hyphen, while the colon is used as the separator between time values (hours, minutes, and seconds). For example, the 6th day of the 1st month of the year 2009 may be written as "2009-01-06" in the extended format or simply as "20090106" in the basic format without ambiguity.

RFC3339, that is a profile of ISO 8601, also states that the offset between local time and UTC is defined as:

time-numoffset = ("+" / "-") time-hour ":" time-minute

As such, should the the O format string should most likely include a colon, right?

[lamweili]

I believe this is what @thernstig is saying.

The date and time portions are using the extended format, which includes - and : delimiters.
Thus, the timezone portion should also be using the extended format, with the : delimiter, for consistency.

2022-01-06T08:47:48.003+0800 -> 2022-01-06T08:47:48.003+08:00

date-format/lib/index.js

Line 30 in 2808365

return timezoneOffset < 0 ? "+" + h + m : "-" + h + m;

- return timezoneOffset < 0 ? "+" + h + m : "-" + h + m; 
+ return (timezoneOffset < 0 ? "+" : "-") + h + ":" + m; 

There seems to be little to no regression as JS handles both cases.

let test1 = new Date("2022-01-06T08:47:48.003+0800");
let test2 = new Date("2022-01-06T08:47:48.003+08:00");
console.log(test1.getTime() === test2.getTime());
// true

Might also want to include a case of +0000 or +00:00 to return Z instead.

- return timezoneOffset < 0 ? "+" + h + m : "-" + h + m; 
+ return timezoneOffset === 0 ? "Z" : (timezoneOffset < 0 ? "+" : "-") + h + ":" + m; 

[thernstig]

@peteriman thank you for that comment. I re-read my original post and must have been very tired when writing it, as it ended quite abruptly without better examples of what I meant, and where the change should be made.

[lamweili]

For more details: #27 (comment)