Source: isFirstDayOfMonth/index.js

  1. import toDate from '../toDate/index'
  2. import requiredArgs from '../_lib/requiredArgs/index'
  4. /**
  5.  * @name isFirstDayOfMonth
  6.  * @category Month Helpers
  7.  * @summary Is the given date the first day of a month?
  8.  *
  9.  * @description
  10.  * Is the given date the first day of a month?
  11.  *
  12.  * ### v2.0.0 breaking changes:
  13.  *
  14.  * - [Changes that are common for the whole library](https://github.com/date-fns/date-fns/blob/master/docs/upgradeGuide.md#Common-Changes).
  15.  *
  16.  * @param {Date|Number} date - the date to check
  17.  * @returns {Boolean} the date is the first day of a month
  18.  * @throws {TypeError} 1 argument required
  19.  *
  20.  * @example
  21.  * // Is 1 September 2014 the first day of a month?
  22.  * var result = isFirstDayOfMonth(new Date(2014, 8, 1))
  23.  * //=> true
  24.  */
  25. export default function isFirstDayOfMonth(dirtyDate) {
  26.   requiredArgs(1, arguments)
  28.   return toDate(dirtyDate).getDate() === 1
  29. }