Refactor PSM1 powershell module into seperate ps1 files

RefactorPSM1.ps1

<#
    .SYNOPSIS
        RefactorPSM1.ps1

    .DESCRIPTION
        RefactorPSM1.ps1

    .NOTES
        For additonal information please contact david@wallis2000.co.uk

    .LINK
        http://blog.wallis2000.co.uk/2019/04/refactoring-psm1-based-modules-into.html
#>

[Cmdletbinding()]
Param(
    [Parameter(Mandatory=$true)]
    [ValidateScript({
        if(-Not ($_ | Test-Path) ){
            throw "File does not exist"
        }
        if(-Not ($_ | Test-Path -PathType Leaf) ){
            throw "The Path argument must be a file. Folder paths are not allowed."
        }
        return $true
    })]
    [System.IO.FileInfo]$PSM1FileName,

    [Parameter(Mandatory=$true)]
    [ValidateScript({
        if(-Not ($_ | Test-Path) ) {
            throw "Folder does not exist"
        }
        if(-Not ($_ | Test-Path -PathType Container)) {
            throw "The Path argument must be a folder. File paths are not allowed."
        }
        return $true
    })]
    [System.IO.FileInfo]$OutputPath
)

$token = $null
$err = $null
$ast = [System.Management.Automation.Language.Parser]::ParseFile($PSM1FileName, [ref]$token, [ref]$err)

$functionDefinitions = $ast.FindAll({
    param(
        [System.Management.Automation.Language.Ast]$Ast
    )

    $Ast -is [System.Management.Automation.Language.FunctionDefinitionAst] `
        -and ($PSVersionTable.PSVersion.Major -lt 5 `
        -or  $Ast.Parent -isnot [System.Management.Automation.Language.FunctionMemberAst])
}, $true)


$OutputPath = "$($OutputPath)\{0}\Public" -f [System.IO.Path]::GetFileNameWithoutExtension($PSM1FileName)

if (-not (Test-Path $outputPath)) {
    $null = New-Item -Path $OutputPath -ItemType Container
}

$PSM1 = @'
# Get public and private function definition files.
$Public  = @( Get-ChildItem -Path $PSScriptRoot\Public\*.ps1  -ErrorAction SilentlyContinue )
$Private = @( Get-ChildItem -Path $PSScriptRoot\Private\*.ps1 -ErrorAction SilentlyContinue )

# Dot source the files
ForEach ($import in @($Public + $Private)) {
    Try {
        . $import.fullname
    }
    Catch {
        Write-Error -Message "Failed to import function $($import.fullname): $_"
    }
}

Export-ModuleMember -Function $Public.Basename
'@


Write-Warning "Only code within functions will be 'refactored'"
$functionDefinitions | ForEach-Object {
    Write-Verbose "Processing Function: $($_.Name)"
    $_.Extent.Text | Out-File (Join-Path -Path $OutputPath -ChildPath "$($_.Name).ps1")
}

# Create a PSM1 file that dot sources all the public functions - by default all are created as 'Public'
$PSM1 | Out-File (Join-Path -Path ($OutputPath | Split-Path -Parent) -ChildPath ([System.IO.Path]::GetFileName($PSM1FileName)))