ConvertTo-Json unboxing single item - json

Question

I am working in PowerShell with a hashtable like so:
When I convert it to JSON notice that the "oranges" key does not contain brackets:
I have tried to accommodate for this when I create my hashtable by doing something like this:
foreach ($Group in ($input | Group fruit)) {
if ($Group.Count -eq 1) {
$hashtable[$Group.Name] = "{" + ($Group.Group | Select -Expand number) + "}"
} else {
$hashtable[$Group.Name] = ($Group.Group | Select -Expand number)
}
}
Which looks fine when I output it as a hashtable but then when I convert to JSON I get this:
I am trying to get that single item also surrounded in []. I found a few things here and one of them took me to this:
https://superuser.com/questions/414650/why-does-powershell-silently-convert-a-string-array-with-one-item-to-a-string
But I don't know how to target just that one key when it only contains a single item.

Answer 1

You want to ensure that all hashtable values are arrays (that is what the curly brackets in the hashtable output and the square brackets in the JSON mean).
Change this code:
if ($Group.Count -eq 1) {
$hashtable[$Group.Name] = "{" + ($Group.Group | Select -Expand number) + "}"
} else {
$hashtable[$Group.Name] = ($Group.Group | Select -Expand number)
}
into this:
$hashtable[$Group.Name] = #($Group.Group | Select -Expand number)
and the problem will disappear.