CFP - Docs - reverse

reverse

```
(anArray: array) => array
```

Reverse an array

const arr = ['a', 'b', 'c']
reverse(arr) // is ['c', 'b', 'a']
const arr = ['a', 'b', 'c']
reverse(arr) // is ['c', 'b', 'a']

Try It

const arr = ['a', 'b', 'c']
reverse(arr) // is ['c', 'b', 'a']
const arr = ['a', 'b', 'c']
reverse(arr) // is ['c', 'b', 'a']

Sometimes we have ordered data and want to reverse it. Below, we run an email provider. Some customers prefer their newest emails to be displayed last. Let's implement this preference by reversing the emails.

Try It

const emailFolders = {
  work: [
    { time: '01:15pm', subject: 'Follow up about review' },
    { time: '10:03am', subject: 'Lunch at Arbys?' },
    { time: '08:52am', subject: 'Meeting at 9 cancelled' },
  ],
  daycare: [
    { time: '03:01pm', subject: 'Emma has been great!' },
    { time: '07:39am', subject: 'Bill adjustment approval' },
  ],
}

const preferMostRecentLast = mapValues(reverse)
const updatedFolders = preferMostRecentLast(emailFolders)

console.log(updatedFolders)
// is {
//   work: [
//     {
//        time: 08:52am
//        subject: Meeting at 9 cancelled
//     }, {
//        time: 10:03am
//        subject: Lunch at Arbys?
//     }, {
//        time: 01:15pm
//        subject: Follow up about review
//     }
//   ]
//   daycare: [
//     {
//        time: 07:39am
//        subject: Bill adjustment approval
//     }, {
//        time: 03:01pm
//        subject: Emma has been great!
//     }
//   ]
// }
type Email = {
  time: string
  subject: string
}
type EmailFolders = Record<string, Email[]>
const emailFolders: EmailFolders = {
  work: [
    { time: '01:15pm', subject: 'Follow up about review' },
    { time: '10:03am', subject: 'Lunch at Arbys?' },
    { time: '08:52am', subject: 'Meeting at 9 cancelled' },
  ],
  daycare: [
    { time: '03:01pm', subject: 'Emma has been great!' },
    { time: '07:39am', subject: 'Bill adjustment approval' },
  ],
}

const preferMostRecentLast = mapValues(reverse<Email[]>)<EmailFolders>
const updatedFolders = preferMostRecentLast(emailFolders)

console.log(updatedFolders)
// is {
//   work: [
//     {
//        time: 08:52am
//        subject: Meeting at 9 cancelled
//     }, {
//        time: 10:03am
//        subject: Lunch at Arbys?
//     }, {
//        time: 01:15pm
//        subject: Follow up about review
//     }
//   ]
//   daycare: [
//     {
//        time: 07:39am
//        subject: Bill adjustment approval
//     }, {
//        time: 03:01pm
//        subject: Emma has been great!
//     }
//   ]
// }

Try It

const emailFolders = {
  work: [
    {
      time: '01:15pm',
      subject: 'Follow up about review',
    },
    {
      time: '10:03am',
      subject: 'Lunch at Arbys?',
    },
    {
      time: '08:52am',
      subject: 'Meeting at 9 cancelled',
    },
  ],
  daycare: [
    {
      time: '03:01pm',
      subject: 'Emma has been great!',
    },
    {
      time: '07:39am',
      subject: 'Bill adjustment approval',
    },
  ],
}

const preferMostRecentLast = mapValues(reverse)
const updatedFolders =
  preferMostRecentLast(emailFolders)

console.log(updatedFolders)
// is {
//   work: [
//     {
//        time: 08:52am
//        subject: Meeting at 9 cancelled
//     }, {
//        time: 10:03am
//        subject: Lunch at Arbys?
//     }, {
//        time: 01:15pm
//        subject: Follow up about review
//     }
//   ]
//   daycare: [
//     {
//        time: 07:39am
//        subject: Bill adjustment approval
//     }, {
//        time: 03:01pm
//        subject: Emma has been great!
//     }
//   ]
// }
type Email = {
  time: string
  subject: string
}
type EmailFolders = Record<string, Email[]>
const emailFolders: EmailFolders = {
  work: [
    {
      time: '01:15pm',
      subject: 'Follow up about review',
    },
    {
      time: '10:03am',
      subject: 'Lunch at Arbys?',
    },
    {
      time: '08:52am',
      subject: 'Meeting at 9 cancelled',
    },
  ],
  daycare: [
    {
      time: '03:01pm',
      subject: 'Emma has been great!',
    },
    {
      time: '07:39am',
      subject: 'Bill adjustment approval',
    },
  ],
}

const preferMostRecentLast = mapValues(
  reverse<Email[]>
)<EmailFolders>
const updatedFolders =
  preferMostRecentLast(emailFolders)

console.log(updatedFolders)
// is {
//   work: [
//     {
//        time: 08:52am
//        subject: Meeting at 9 cancelled
//     }, {
//        time: 10:03am
//        subject: Lunch at Arbys?
//     }, {
//        time: 01:15pm
//        subject: Follow up about review
//     }
//   ]
//   daycare: [
//     {
//        time: 07:39am
//        subject: Bill adjustment approval
//     }, {
//        time: 03:01pm
//        subject: Emma has been great!
//     }
//   ]
// }