Piping an empty object has a count of 1 - function

Question

I can't seem to get this function quite right. I want to pass it an object and if the object is empty, return 1, else count items in the object and increment by 1.
Assuming the following function "New-Test":
function New-Test
{
[cmdletbinding()]
Param
(
[Parameter(ValueFromPipeline=$true,ValueFromPipelineByPropertyName=$true)]
[object[]]$Object
#[object]$object
)
Begin
{
$oData=#()
}
Process
{
"Total objects: $($object.count)"
if($Object.count -gt 0)
{
$oData += [pscustomobject]#{
Name = $_.Name
Value = $_.Value
}
}
Else
{
Write-Verbose "No existing object to increment. Assuming first entry."
$oData = [pscustomobject]#{Value = 0}
}
}
End
{
$LatestName = ($oData | Sort-Object -Descending -Property Value | Select -First 1).value
[int]$intNum = [convert]::ToInt32($LatestName, 10)
$NextNumber = "{0:00}" -f ($intNum+1)
$NextNumber
}
}
And the following test hashtable:
#Create test hashtable:
$a = 00..08
$obj = #()
$a | foreach-object{
$obj +=[pscustomobject]#{
Name = "TestSting" + "{0:00}" -f $_
Value = "{0:00}" -f $_
}
}
As per the function above, if I pass it $Obj, I get:
$obj | New-Test -Verbose
Total objects: 1
Total objects: 1
Total objects: 1
Total objects: 1
Total objects: 1
Total objects: 1
Total objects: 1
Total objects: 1
Total objects: 1
09
Which is as expected. However, if I pass it $Obj2:
#Create empty hash
$obj2 = $null
$obj2 = #{}
$obj2 | New-Test -Verbose
I get:
Total objects: 1
Exception calling "ToInt32" with "2" argument(s): "Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: startIndex"
At line:33 char:9
+ [int]$intNum = [convert]::ToInt32($LatestName, 10)
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : NotSpecified: (:) [], MethodInvocationException
+ FullyQualifiedErrorId : ArgumentOutOfRangeException
01
I don't understand why $object.count is 1, when there's nothing in the hashtable.
If I change the parameter, $object's type from [object[]] to [object], the empty hashtable test results in:
$obj2 | New-Test -Verbose
Total objects: 0
VERBOSE: No existing object to increment. Assuming first entry.
01
Which is what I'd expect, however, if I run the first test, it results in:
$obj | New-Test -Verbose
Total objects:
VERBOSE: No existing object to increment. Assuming first entry.
Total objects:
VERBOSE: No existing object to increment. Assuming first entry.
This time $objects has nothing in it.
I'm sure it's simple, but I can't fathom this one out. Any help is appreciated.
P.S. PowerShell 5.1

Answer 1

$obj2 is a hashtable, not an array. Hashtables are not enumerated by default, so the hashtable itself is the one object. If you want to loop through an hashtable using the pipeline you need to use $obj2.GetEnumerator().
#{"hello"="world";"foo"="bar"} | Measure-Object | Select-Object Count
Count
-----
1
#{"hello"="world";"foo"="bar"}.GetEnumerator() | Measure-Object | Select-Object Count
Count
-----
2