@saas-ui/date-picker/src/date-utils.ts

Chakra UI - Date Picker Component

import { CalendarDateTime, DateFormatter } from '@internationalized/date'
import { DateRangeValue, DateValue } from './types'

export const isDateInRange = (
  date: DateValue | null,
  range: DateRangeValue
) => {
  if (!date || !range) {
    return false
  }
  return !!(
    range?.start &&
    date.compare(range.start) >= 0 &&
    range?.end &&
    date.compare(range.end) <= 0
  )
}

export function parseDateString(
  date: string,
  locale: string,
  timeZone: string
) {
  const regex = createRegex(locale, timeZone)
  const { year, month, day } = extract(regex, date) ?? {}

  if (
    year != null &&
    year.length === 4 &&
    month != null &&
    +month <= 12 &&
    day != null &&
    +day <= 31
  ) {
    return new CalendarDateTime(+year, +month, +day)
  }

  const time = Date.parse(date)
  if (!isNaN(time)) {
    const date = new Date(time)
    return new CalendarDateTime(
      date.getFullYear(),
      date.getMonth() + 1,
      date.getDate()
    )
  }
}

function createRegex(locale: string, timeZone: string) {
  const formatter = new DateFormatter(locale, {
    day: 'numeric',
    month: 'numeric',
    year: 'numeric',
    timeZone,
  })
  const parts = formatter.formatToParts(new Date(2000, 11, 25))
  return parts
    .map(({ type, value }) =>
      type === 'literal' ? value : `((?!=<${type}>)\\d+)`
    )
    .join('')
}

function extract(pattern: string | RegExp, str: string) {
  const matches = str.match(pattern)
  return pattern
    .toString()
    .match(/<(.+?)>/g)
    ?.map((group) => {
      const groupMatches = group.match(/<(.+)>/)
      if (!groupMatches || groupMatches.length <= 0) {
        return null
      }
      return group.match(/<(.+)>/)?.[1]
    })
    .reduce((acc: Record<string, string | null>, curr, index) => {
      if (!curr) return acc
      if (matches && matches.length > index) {
        acc[curr] = matches[index + 1]
      } else {
        acc[curr] = null
      }
      return acc
    }, {} as { year: string; month: string; day: string })
}