Splitting Multi-valued JSON elements into an Array with PowerShell

Question

I'm working with some JSON data in PowerShell. Some elements are multi-valued, delimited with a semi-colon, but its not always the same elements that are multi-valued. I would like to convert multi-valued elements, where ever they may occur, into JSON arrays.

I'm having trouble doing this. I've worked out a way to identify which elements are multi-valued, but am unsure how to split them when outputting the entire JSON. Do I need to construct a custom PSObject and breakout multi-valued elements into an array before exporting as JSON? That seems like a lot of overhead for a simple task.

Starting example

{
  "Title": "Civil War Diary - Original and Transcript",
  "Date Created": "1863",
  "Access Rights": "Open Access",
  "Identifier": "e9f44e22b9a285c1c3e2ac0307d113f3",
  "Resource Type": "Text; Still Image"
}

Desired output

{
    "Title": "Civil War Diary - Original and Transcript",
    "Date Created": "1863",
    "Access Rights": "Open Access",
    "Identifier": "e9f44e22b9a285c1c3e2ac0307d113f3",
    "Resource Type": [
        "Text",
        "Still Image"
    ]
}

Answer 1

As mentioned in the comments above, this data originates as a CSV file. I was able to add three lines to a ForEach-Object loop where I was trimming the fields to cast multi-valued fields to an array, split on the delimiter.

$csv | Foreach-Object {
    foreach ($property in $_.PSObject.Properties) {
        # Cast multi-valued fields to an array
        if ($property.value -like "*;*") {
            $property.value = [array]$property.value.Split(";")
        }
        # Trim fields
        $property.value = $property.value.trim()
    }
}