Get latest element with certain prefix in JMESPath

I have a JSON input like that:

{
  "details": [
    {
      "file": [
        "xxx-abc"
      ],
      "filePushedAt": "2021-10-25T09:31:39+02:00"
    },
    {
      "file": [
        "xxx-dfg"
      ],
      "filePushedAt": "2021-11-08T16:24:05+01:00"
    },
    {
      "file": [
        "hij"
      ],
      "filePushedAt": "2022-01-26T15:24:17+01:00"
    },
    {
      "file": [
        "xxx-klm"
      ],
      "filePushedAt": "2022-01-27T15:24:18+01:00"
    },
    {
      "file": [
        "opr"
      ],
      "filePushedAt": "2021-11-28T09:31:39+02:00"
    }
  ]
}

Using JMESPath I need to get the latest file (latest filePushedAt) which consists xxx prefix in file array.

I am able to extract files names in order by using

sort_by(details,& filePushedAt)[*].file[*] 

but cannot complete the task. I'm wondering if it is even possible without jq?

In order to filter the file arrays nested in the details one, you need to filter at the details level.
You will need the starts_with function in order to filter all elements of the file arrays for the prefix xxx.

So, knowing all this, we have the query:

details[?file[?starts_with(@,`xxx`)]]

That gives us the filtered array:

[
  {
    "file": [
      "xxx-abc"
    ],
    "filePushedAt": "2021-10-25T09:31:39+02:00"
  },
  {
    "file": [
      "xxx-dfg"
    ],
    "filePushedAt": "2021-11-08T16:24:05+01:00"
  },
  {
    "file": [
      "xxx-klm"
    ],
    "filePushedAt": "2022-01-27T15:24:18+01:00"
  }
]

Now, to fulfil you requirement, you still need, a sort_by, a reverse, because sort_by does not have an option to sort ascending or descending, and to select the first item of the array, with [0].

So, now, given the query

reverse(sort_by(details[?file[?starts_with(@,`xxx`)]], &filePushedAt))[0]

You do have the object you were looking for:

{
  "file": [
    "xxx-klm"
  ],
  "filePushedAt": "2022-01-27T15:24:18+01:00"
}