Get-ChildItem -Depth for PS 4.0

Get-ChildItemDeep.ps1

function Get-ChildItemDeep
{
  param(
    [Parameter(ParameterSetName='Items', Position=0, ValueFromPipeline=$true, ValueFromPipelineByPropertyName=$true)]
    [string[]]
    ${Path},

    [Parameter(Position=1)]
    [string]
    ${Filter},

    [Parameter(Mandatory=$true)]
    [int]
    ${Depth}
  )

  # Make a copy of the params for `Get-ChildItem`
  $GCIParams = @{}
  foreach($ParamName in $PSBoundParameters.Keys.Where({$_ -ne 'Depth'})){
    $GCIParams[$ParamName] = $PSBoundParameters[$ParamName]
  }

  # Decrease depth for next call
  $PSBoundParameters['Depth']--

  # Call Get-ChildItem
  Get-ChildItem @GCIParams |ForEach-Object {
    $_
    # Recurse if appropriate
    if($_.PSIsContainer -and $Depth -gt 1){
      $PSBoundParameters['Path'] = $_.FullName
      Get-ChildItemDeep @PSBoundParameters
    }
  }
}