Functions for Powershell 4 to zip files or directories (.NET Framework 4.5 Required)

PsZip.psm1

Add-Type -assembly 'System.IO.Compression.FileSystem'

function Zip-Directory([string]$Directory, $Destination) {
    if (!(Test-Path $Directory -PathType Container)) {
        throw "Directory does not exist: $Directory"
    }

    $Directory = (Resolve-Path $Directory).Path.TrimEnd('\')
    
    if ($null -ne $Destination) {
        if (!(Test-Path $Destination -PathType Container)) {
            throw "Destination does not exist: $Destination"
        }

        $Destination = (Resolve-Path $Destination).Path.TrimEnd('\')

        if (($Destination + '\').StartsWith(($Directory + '\'))) {
            throw "Destination cannot be in the Directory being zipped"
        }

        $ZipPath = [System.IO.Path]::Combine($Destination, [System.IO.Path]::GetFileName($Directory) + ".zip")
    }
    else {
        $ZipPath = [System.IO.Path]::Combine([System.IO.Path]::GetDirectoryName($Directory), [System.IO.Path]::GetFileName($Directory) + ".zip")
    }

    if (Test-Path $ZipPath -PathType Leaf) {
        throw "Zip File already exists: $ZipPath"
    }

    [System.IO.Compression.ZipFile]::CreateFromDirectory($Directory, $ZipPath)
}

function Zip-File([string]$File, $Destination) {
    if (!(Test-Path $File -PathType Leaf)) {
        throw "File does not exist: $File"
    }

    $File = (Resolve-Path $File).Path.TrimEnd('\')

    if ($null -ne $Destination) {
        if (!(Test-Path $Destination -PathType Container)) {
            throw "Destination does not exist: $Destination"
        }

        $Destination = (Resolve-Path $Destination).Path.TrimEnd('\')

        $ZipPath = [System.IO.Path]::Combine($Destination, [System.IO.Path]::GetFileNameWithoutExtension($File) + ".zip")
    }
    else {
        $ZipPath = [System.IO.Path]::ChangeExtension($File, ".zip")
    }

    if (Test-Path $ZipPath -PathType Leaf) {
        throw "Zip File already exists: $ZipPath"
    }
       
    $ZipFile = [System.IO.Compression.ZipFile]::Open($ZipPath, [System.IO.Compression.ZipArchiveMode]::Create)
    $Entry = [System.IO.Compression.ZipFileExtensions]::CreateEntryFromFile($ZipFile, $File, [System.IO.Path]::GetFileName($File))

    $ZipFile.Dispose()
}