PowerShell: Function doesn't have proper return value

Question

I wrote a powershell script to compare the content of two folders: ``` $Dir1 ="d:\TEMP\Dir1" $Dir2 ="d:\TEMP\Dir2" function Test-Diff($Dir1, $Dir2) { $fileList1 = Get-ChildItem $Dir1 -Recurse | Where-Object {!$_.PsIsContainer} | Get-Item | Sort-Object -Property Name $fileList2 = Get-ChildItem $Dir2 -Recurse | Where-Object {!$_.PsIsContainer} | Get-Item | Sort-Object -Property Name if($fileList1.Count -ne $fileList2.Count) { Write-Host "Following files are different:" Compare-Object -ReferenceObject $fileList1 -DifferenceObject $fileList2 -Property Name -PassThru | Format-Table FullName return $false } return $true } $i = Test-Diff $Dir1 $Dir2 if($i) { Write-Output "Test OK" } else { Write-Host "Test FAILED" -BackgroundColor Red } ``` If I set a break point on `Compare-Object`, and I run this command in console, I get the list of differences. If I run the whole script, I don't get any output. Why? I'm working in PowerGUI Script Editor, but I tried the normal ps console too. EDIT: The p…

Accepted Answer

I've found the answer here: http://martinzugec.blogspot.hu/2008/08/returning-values-from-fuctions-in.html

Functions like this:

```
Function bar {
 [System.Collections.ArrayList]$MyVariable = @()
 $MyVariable.Add("a")
 $MyVariable.Add("b")
 Return $MyVariable
}
```

uses a PowerShell way of returning objects: @(0,1,"a","b") and not @("a","b")

To make this function work as expected, you will need to redirect output to null:

```
Function bar {
 [System.Collections.ArrayList]$MyVariable = @()
 $MyVariable.Add("a") | Out-Null
 $MyVariable.Add("b") | Out-Null
 Return $MyVariable
}
```

In our case, the function has to be refactored as suggested by Koliat.

PowerShell: Function doesn't have proper return value

Solution

Problem