doc: add note for longDateFormat

dayjs / dayjs-website

⏰Day.js website repo

http://day.js.org/

MIT License

65 stars 228 forks source link

Closed ZouYouShun closed 1 year ago

ZouYouShun commented 1 year ago

add a note for longDateFormat with 'L' to prevent user miss meet issues with Cannot read properties of undefined (reading 'L')