Sort an array of objects containing a date array

Question

I am currently attempting to sort an array of objects, and each object contains an array of dates. The data structure looks like the following:

const array = [
  {
    name: "Judith",
    cal: {
      ti: [
        "2021-03-09T15:00:00Z",
        "2021-03-09T15:30:00Z",
        "2021-03-16T14:00:00Z"
      ]
    }
  },
  {
    name: "billy",
    cal: {
      ti: [
        "2021-03-05T14:30:00Z",
        "2021-03-08T14:00:00Z",
        "2021-03-08T14:30:00Z"
      ]
    }
  }
]

I am attempting to sort the array based on the closest available time to now using the date library known as dayjs . I am attempting to compare each array of dates using the diff method within the dayjs package like so:

const test = array.map(i => i.cal.ti.sort((a, b) => {
 dayjs(a).diff(dayjs(b))
}))

console.log(test)

I would like to sort the objects contained within the array returning the object with the closest available time first and so on and so forth. I am noticing I am returning incorrectly within the sort and I believe I have a whole mess of issues going on as well, where I am not comparing the dates correctly causing my sort of the array to fail.

Attached is a repl.it for debugging:

https://repl.it/@rterrell25/LegalJaggedCoordinate#index.js

Answer 1

In your test data, the dates are already sorted, so that might skew your perception of what's going on already.

I re-ordered the test data so that they start un-sorted and then changed your sort very slightly so that it returns either -1 or 1 (which is what sort functions should be returning):

const array = [
  {
    name: "Judith",
    cal: {
      ti: [
        "2021-03-16T14:00:00Z",
        "2021-03-09T15:00:00Z",
        "2021-03-09T15:30:00Z",
      ]
    }
  },
  {
    name: "billy",
    cal: {
      ti: [
        "2021-03-08T14:00:00Z",
        "2021-03-05T14:30:00Z",
        "2021-03-08T14:30:00Z"
      ]
    }
  }
]
const test = array.map(i => i.cal.ti.sort((a, b) => (dayjs(a).isAfter(dayjs(b)) ? 1 : -1)))
 
 console.log(test)

Update :

const test = array.sort((a,b) => {
  let aFirst = a.cal.ti.map(i => dayjs(i)).sort((a1,b1) => a1.isAfter(b1) ? 1 : -1)[0]
  let bFirst = b.cal.ti.map(i => dayjs(i)).sort((a1,b1) => a1.isAfter(b1) ? 1 : -1)[0]
  return aFirst.isAfter(bFirst) ? 1 : -1
})
 console.log(test)

This method of sorting dayjs objects comes from a suggestion here ( https://github.com/iamkun/dayjs/issues/328 )

Regarding your note about returning -- if you use {} to wrap your function body, you should be using the return inside the braces. You'll note that in my sort function, there aren't any braces -- in this case the return value from the one-line function is taken automatically.

Answer 2

try this:

 const array = [ { name: "Judith", cal: { ti: [ "2021-03-16T14:00:00Z", "2021-03-09T15:00:00Z", "2021-03-09T15:30:00Z", "2021-03-19T15:30:00Z", "2021-02-19T15:30:00Z", ] } }, { name: "billy", cal: { ti: [ "2021-03-08T14:00:00Z", "2021-03-05T14:30:00Z", "2021-02-25T14:30:00Z", "2021-03-25T14:30:00Z", "2021-03-08T14:30:00Z" ] } } ]; const now = new Date(); array.forEach(i => i.cal.ti.sort((a, b) => Math.abs(new Date(a) - now) - Math.abs(new Date(b) - now) )); array.sort((a, b) => Math.abs(new Date(a.cal.ti[0]) - now) - Math.abs(new Date(b.cal.ti[0]) - now) ); console.log(array);