PowerShell GetSteppablePipeline

GetSteppablePipeline_Demo.ps1

function Write-Log {
    param(
        [Parameter(ValueFromPipeline, Mandatory)]
        [object] $InputObject,

        [parameter(Mandatory)]
        [string] $Path,

        [parameter()]
        [switch] $PassThru
    )

    begin { 
        $scriptBlock = { Set-Content -LiteralPath $Path }
        $steppablePipeline = $scriptBlock.GetSteppablePipeline( $myInvocation.CommandOrigin )
        $steppablePipeline.Begin( $PSCmdlet )
    }
    process {
        $steppablePipeline.Process( "$(Get-Date) - $InputObject" )
        if($PassThru.IsPresent) { $InputObject }
    }
    end { 
        $steppablePipeline.End()
    }
}

$FileList = Get-ChildItem -Path $PSScriptRoot\* -Include '*.csv', '*.xlsx' |
    Write-Log -Path "$PSScriptRoot\TestLog.log" -PassThru

$FileList