gets file count and total (recursive) size of every folder

Get-DirectoryInfo.ps1

# This is not really good... if you want the real deal, check out:
# https://github.com/santisq/PSTree
function Get-DirectoryInfo {
    [CmdletBinding()]
    param(
        [Parameter(Mandatory, ValueFromPipelineByPropertyName, ValueFromPipeline)]
        [alias('FullName')]
        [ValidateScript({
            if(Test-Path $_ -PathType Container) {
                return $true
            }
            throw 'Directories only!'
        })]
        [string[]] $LiteralPath,

        [Parameter()]
        [switch] $Force
    )

    begin {
        class Tree {
            [string] $FullName
            [Int64] $Count
            [Int64] $Size
            [string] $FriendlySize

            [void] AddSize([Int64] $Size) {
                $this.Size += $Size
            }

            [void] SetFriendlySize() {
                # Inspired from https://stackoverflow.com/a/40887001/15339544

                $suffix = "B", "KB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB"
                $index  = 0
                $length = $this.Size

                while ($Length -ge 1kb) {
                    $Length /= 1kb
                    $index++
                }

                $this.FriendlySize = [string]::Format(
                    '{0} {1}',
                    [math]::Round($Length, 2), $suffix[$index]
                )
            }
        }

        $indexer = [ordered]@{}
        $stack   = [Collections.Generic.Stack[IO.DirectoryInfo]]::new()
        $PSBoundParameters['Directory'] = $true
    }
    process {
        foreach($folder in $LiteralPath | Get-Item) {
            $stack.Push($folder)
        }

        while($stack.Count) {
            $PSBoundParameters['LiteralPath'] = $stack.Pop()
            foreach($folder in Get-ChildItem @PSBoundParameters) {
                $stack.Push($folder)
                $count = 0
                $size  = 0

                foreach($file in $folder | Get-ChildItem -File -Force) {
                    $count++
                    $size += $file.Length
                }

                $indexer[$folder.FullName] = [Tree]@{
                    FullName = $folder.FullName
                    Count    = $count
                    Size     = $size
                }

                $parent = $folder.Parent

                while($parent -and $indexer.Contains($parent.FullName)) {
                    $indexer[$parent.FullName].AddSize($size)
                    $parent = $parent.Parent
                }
            }
        }

        $output = $indexer.PSBase.Values
        if($output.Count) {
            $output.SetFriendlySize()
            $output
        }
        $indexer.Clear()
    }
}