Filter JSON in Powershell - json

Question

I have the following JSON in a Powershell variable:
{
"Object1": {
"name": "asdf1",
"criteria": 2
},
"Object2": {
"name": "asdf2",
"criteria": 1
}
}
I want to get JSON where the value of criteria is 1. The result therefore should look as follows:
{
"Object2": {
"name": "asdf2",
"criteria": 1
}
}
I made an attempt with the following code:
$json | Get-ObjectMembers | Select-Object | where { $_.value.criteria -eq 1 };
While this basically goes into the right direction, it is not what I want exactly, because the result looks like this:
{
"name": "asdf2",
"criteria": 1
}
See that the Object2 information is lost and one depth-level is lost.
How can I achieve the desired result as shown above?

Answer 1

In essence, you're looking to only retain properties of interest from your single input object or, to put it differently, to remove properties you're not interested in.
Here's a PSv4+ solution:
$json = #'
{
"Object1": {
"name": "asdf1",
"criteria": 2
},
"Object2": {
"name": "asdf2",
"criteria": 1
}
}
'#
($json | ConvertFrom-Json).psobject.Properties.
Where({ $_.Value.criteria -eq 1 }).
ForEach({ [pscustomobject] #{ $_.Name = $_.Value } }) |
ConvertTo-Json
The above yields:
{
"Object2": {
"name": "asdf2",
"criteria": 1
}
}

Answer 2

The jq solution. with_entries temporarily turns a list of properties into key and value pairs. https://stedolan.github.io/jq/manual/#to_entries,from_entries,with_entries (section id's in html come in handy) (Json creators don't believe in arrays?)
$json = '{
"Object1": {
"name": "asdf1",
"criteria": 2
},
"Object2": {
"name": "asdf2",
"criteria": 1
}
}'
$json | jq 'with_entries(select(.value.criteria == 1))'
{
"Object2": {
"name": "asdf2",
"criteria": 1
}
}