55 lines
1.6 KiB
Markdown
55 lines
1.6 KiB
Markdown
|
# Unicode Tokens
|
||
|
|
|
||
|
|
Starting with v2, `format` and `parse` use [Unicode tokens].
|
||
|
|
|
||
|
|
The tokens are different from Moment.js and other libraries that opted to use
|
||
|
|
custom formatting rules. While usage of a standard ensures compatibility and
|
||
|
|
the future of the library, it causes confusion that this document intends
|
||
|
|
to resolve.
|
||
|
|
|
||
|
|
## Popular mistakes
|
||
|
|
|
||
|
|
There are 4 tokens that cause most of the confusion:
|
||
|
|
|
||
|
|
- `D` and `DD` that represent the day of a year (1, 2, ..., 365, 366)
|
||
|
|
are often confused with `d` and `dd` that represent the day of a month
|
||
|
|
(1, 2, ..., 31).
|
||
|
|
|
||
|
|
- `YY` and `YYYY` that represent the local week-numbering year (44, 01, 00, 17)
|
||
|
|
are often confused with `yy` and `yyyy` that represent the calendar year.
|
||
|
|
|
||
|
|
```js
|
||
|
|
// ❌ Wrong!
|
||
|
|
format(new Date(), "YYYY-MM-DD");
|
||
|
|
//=> 2018-10-283
|
||
|
|
|
||
|
|
// ✅ Correct
|
||
|
|
format(new Date(), "yyyy-MM-dd");
|
||
|
|
//=> 2018-10-10
|
||
|
|
|
||
|
|
// ❌ Wrong!
|
||
|
|
parse("11.02.87", "D.MM.YY", new Date()).toString();
|
||
|
|
//=> 'Sat Jan 11 1986 00:00:00 GMT+0200 (EET)'
|
||
|
|
|
||
|
|
// ✅ Correct
|
||
|
|
parse("11.02.87", "d.MM.yy", new Date()).toString();
|
||
|
|
//=> 'Wed Feb 11 1987 00:00:00 GMT+0200 (EET)'
|
||
|
|
```
|
||
|
|
|
||
|
|
To help with the issue, `format` and `parse` functions won't accept
|
||
|
|
these tokens without `useAdditionalDayOfYearTokens` option for `D` and `DD` and
|
||
|
|
`useAdditionalWeekYearTokens` options for `YY` and `YYYY`:
|
||
|
|
|
||
|
|
```js
|
||
|
|
format(new Date(), "D", { useAdditionalDayOfYearTokens: true });
|
||
|
|
//=> '283'
|
||
|
|
|
||
|
|
parse("365+1987", "DD+YYYY", new Date(), {
|
||
|
|
useAdditionalDayOfYearTokens: true,
|
||
|
|
useAdditionalWeekYearTokens: true,
|
||
|
|
}).toString();
|
||
|
|
//=> 'Wed Dec 31 1986 00:00:00 GMT+0200 (EET)'
|
||
|
|
```
|
||
|
|
|
||
|
|
[Unicode tokens]: https://www.unicode.org/reports/tr35/tr35-dates.html#Date_Field_Symbol_Table
|