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diff --git a/node_modules/date-fns/docs/unicodeTokens.md b/node_modules/date-fns/docs/unicodeTokens.md new file mode 100644 index 0000000..5daf282 --- /dev/null +++ b/node_modules/date-fns/docs/unicodeTokens.md @@ -0,0 +1,54 @@ +# 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 |
