CFP - Docs - isAtOrBefore

isAtOrBefore

(date1: date) => (date2: date) => boolean

Test if a date is the same as or before another

Try It

const janFirst2025 = new Date('2025 1 1')
const isAtOrBeforeJanFirst2025 = isAtOrBefore(janFirst2025)

const decFirst2024 = new Date('2024 12 1')
isAtOrBeforeJanFirst2025(decFirst2024) // is true

const now = new Date()
isAtOrBeforeJanFirst2025(now) // is false

isAtOrBeforeJanFirst2025(janFirst2025) // is true
const janFirst2025 = new Date('2025 1 1')
const isAtOrBeforeJanFirst2025 = isAtOrBefore(janFirst2025)

const decFirst2024 = new Date('2024 12 1')
isAtOrBeforeJanFirst2025(decFirst2024) // is true

const now = new Date()
isAtOrBeforeJanFirst2025(now) // is false

isAtOrBeforeJanFirst2025(janFirst2025) // is true

Try It

const janFirst2025 = new Date('2025 1 1')
const isAtOrBeforeJanFirst2025 =
  isAtOrBefore(janFirst2025)

const decFirst2024 = new Date('2024 12 1')
isAtOrBeforeJanFirst2025(decFirst2024) // is true

const now = new Date()
isAtOrBeforeJanFirst2025(now) // is false

isAtOrBeforeJanFirst2025(janFirst2025) // is true
const janFirst2025 = new Date('2025 1 1')
const isAtOrBeforeJanFirst2025 =
  isAtOrBefore(janFirst2025)

const decFirst2024 = new Date('2024 12 1')
isAtOrBeforeJanFirst2025(decFirst2024) // is true

const now = new Date()
isAtOrBeforeJanFirst2025(now) // is false

isAtOrBeforeJanFirst2025(janFirst2025) // is true

Sometimes we need to compare dates. Below, we want to clean up our email. Let's archive any that are at least a year old.

Try It

// assume today is 2025 1 15
const oneYearAgo = new Date('2024 1 15')

const emails = [
  {
    subject: 'Policy renewal',
    received: new Date('2024 1 15'),
  },
  {
    subject: 'Soccer league starting soon',
    received: new Date('2024 1 16'),
  },
]

const shouldArchive = compose([get('received'), isAtOrBefore(oneYearAgo)])
const archive = keepWhen(shouldArchive)
const emailsToArchive = archive(emails)

console.log(emailsToArchive)
// is [
//   {
//     subject: 'Policy renewal',
//     received: 2024 1 15
//   }
// ]
// assume today is 2025 1 15
const oneYearAgo = new Date('2024 1 15')

type Email = {
  subject: string
  received: Date
}

const emails: Email[] = [
  {
    subject: 'Policy renewal',
    received: new Date('2024 1 15'),
  },
  {
    subject: 'Soccer league starting soon',
    received: new Date('2024 1 16'),
  },
]

const shouldArchive = compose([
  get('received')<Email>,
  isAtOrBefore(oneYearAgo),
])
const archive = keepWhen(shouldArchive)<Email[]>
const emailsToArchive = archive(emails)

console.log(emailsToArchive)
// is [
//   {
//     subject: 'Policy renewal',
//     received: 2024 1 15
//   }
// ]

Try It

// assume today is 2025 1 15
const oneYearAgo = new Date('2024 1 15')

const emails = [
  {
    subject: 'Policy renewal',
    received: new Date('2024 1 15'),
  },
  {
    subject: 'Soccer league starting soon',
    received: new Date('2024 1 16'),
  },
]

const shouldArchive = compose([
  get('received'),
  isAtOrBefore(oneYearAgo),
])
const archive = keepWhen(shouldArchive)
const emailsToArchive = archive(emails)

console.log(emailsToArchive)
// is [
//   {
//     subject: 'Policy renewal',
//     received: 2024 1 15
//   }
// ]
// assume today is 2025 1 15
const oneYearAgo = new Date('2024 1 15')

type Email = {
  subject: string
  received: Date
}

const emails: Email[] = [
  {
    subject: 'Policy renewal',
    received: new Date('2024 1 15'),
  },
  {
    subject: 'Soccer league starting soon',
    received: new Date('2024 1 16'),
  },
]

const shouldArchive = compose([
  get('received')<Email>,
  isAtOrBefore(oneYearAgo),
])
const archive = keepWhen(shouldArchive)<Email[]>
const emailsToArchive = archive(emails)

console.log(emailsToArchive)
// is [
//   {
//     subject: 'Policy renewal',
//     received: 2024 1 15
//   }
// ]