VCardTime.fromDateAndOrTimeString gives wrong results

[dvtate]

The algorithm used in VCardTime.fromDateAndOrTimeString gives wrong results even for the example values in rfc-6350. The algorithm appears the same in the current live version as it is in the master branch so definitely worth fixing. I'll take a look at the algorithm and try to fix it unless I'm using this function incorrectly.

Example

• 19961022T141234 gives
  year: 1996
  month: null -- should be 10
  day: null -- should be 22
  hour: 14
  minute: 23 -- should be 12
  second: null -- should be 34

Demo

import ICAL from 'ical.js';

const tests = [
    '19961022T140000',
    '--1022T1400',
    '---22T14',
    '19850412',
    '1985-04',
    '1985',
    '--0412',
    '---12',
    'T102200',
    'T1022',
    'T10',
    'T-2200',
    'T--00',
    'T102200Z',
    'T102200-0800',
    '19961022T140000',
    '19961022T140000Z',
    '19961022T140000-05',
    '19961022T140000-0500',
    '19961022T141234-0500',
];

tests
    .map(s => ICAL.VCardTime.fromDateAndOrTimeString(s, 'date-and-or-time'))
    .forEach((t, i) => console.log(tests[i],'\n\t', t.toString(),'\n\t', t.toICALString()));

[dvtate]

Here's a big, ugly, slow regex that seems to pass all the test cases I've been able to find.

    const dateRegex =
        /(?:^(?<year>[0-9]{4})(?<month>[01][0-9])(?<day>[0-3][0-9])$)/.source
        + /|(?:^(?<year>(?:\+[0-9]+)?[0-9]{4})-(?<month>[01][0-9])-(?<day>[0-3][0-9])$)/.source
        + /|(?:^--(?<month>[01][0-9])(?<day>[0-3][0-9])$)/.source
        + /|(?:^---(?<day>[0-3][0-9])$)/.source
        + /|(?:^(?<year>[0-9]{4})-(?<month>[01][0-9])$)/.source
        + /|(?:^(?<year>[0-9]{4})(?<month>[01][0-9])$)/.source
        + /|(?:^(?<year>[0-9]{4})$)/.source;
    const timeRegex =
        /(?:^(?<hours>[0-2][0-9])(?<mins>[0-6][0-9])(?<secs>[0-6][0-9])(?<zone>Z|(?:[+\-][0-2][0-9](?:[0-2][0-9])?))?$)/.source
        + /|(?:^(?<hours>[0-2][0-9]):(?<mins>[0-6][0-9]):(?<secs>[0-6][0-9])(?<zone>Z|(?:[+\-][0-2][0-9](?::[0-2][0-9])?))?$)/.source
        + /|(?:^(?<hours>[0-2][0-9])(?<mins>[0-6][0-9])(?<secs>[0-6][0-9])$)/.source
        + /|(?:-(?<mins>[0-6][0-9])(?<secs>[0-6][0-9])$)/.source
        + /|(?:--(?<secs>[0-6][0-9])$)/.source
        + /|(?:^(?<hours>[0-2][0-9])(?<mins>[0-6][0-9])$)/.source
        + /|(?:^(?<hours>[0-2][0-9])$)/.source;

Note that in your utc offset parser it expects there to be a colon between the hour and minutes but in every single vcard spec the colon is either optional or explicitly forbidden... so that would probably need to be modified.