How can I access Powershell PSCustomObject properties? - powershell

Question

I'm processing through Powershell script some API result processing.
API data (json) come from this :
$tree = Invoke-WebRequest -Uri "xxxxxxxxmonURLxxxxxxxxxx/130333"
$children = ($tree.Content | ConvertFrom-Json).data.12345.children
Then I loop through $children object using | ForEach
$_ within loop has "147852" as $_.Name, and the following object as $_.Definition
I'd like to parse the object within $_.Definition but cannot figure out how to access it.
The Definition object looks like this:
TypeName : System.Management.Automation.PSCustomObject
Name MemberType Definition
---- ---------- ----------
147852 NoteProperty System.Management.Automation.PSCustomObject 147852=#{nodeType=node; name=test1; flag=N0; creationDate=2022-02-17T14:50:16+00:00; hasAlerts=False; children=}
And I wish to access any property within the 147852 key (such as nodeType, name, flag, ..., children).
$_.147852 outputs an error saying 147852 was not found.
Thanks.
API json returned:
{
"data": {
"130333": {
"nodeType": "node",
"name": "Test name",
"flag": "N0",
"children": {
"147852": {
"nodeType": "node",
"name": "test1",
"flag": "N0",
"hasAlerts": false,
"children": {
"147853": {
"nodeType": "node",
"name": "test2",
"flag": "N0",
"children": {
"NP12-N9-S4": {
"nodeType": "agent",
"name": "Win10",
"type": "S"
}
}
}
}
}
}
}
}

Answer 1

Jeroen Mostert provided the crucial pointer in the comments, and Bender the Greatest links to what is effectively a duplicate question, but given that the latter is hashtable-focused, let me recapitulate the problem in the context of custom objects ([pscustomobject]):
Leaving the accidental use of Get-Member out of the picture, your problem ultimately boils down to a parser bug in PowerShell (see GitHub issue #14036):
To avoid it, quote property names that look like numbers - e.g., to access property 147852 on object $obj, use $obj.'147852'
Strictly speaking, the bug only surfaces if you attempt an additional (nested) property access:
# Nested sample custom object.
$obj = [pscustomobject] #{ 147852 = [pscustomobject] #{ name = 'test1' } }
# OK - number-like property is accessed without quoting, but *not nested*.
# However, $obj.'147852' is preferable.
$obj.147852
# *Nested* property access:
# !! BUG triggers error: "Missing property name after reference operator."
$obj.147852.name
# OK: Quoting avoids the problem.
$obj.'147852'.name # -> 'test1'