Get-ADAttributeAlias.ps1

function Get-ADAttributeAlias {
    <#
    .SYNOPSIS
        Gets the names of the aliased attributes from the ActiveDirectory module.

    .DESCRIPTION
        Users reflection to discover the names of the attribute aliases available to filters.
    

    .EXAMPLE
        Get-ADAttributeAlias

        Displays the atttribute aliases available for User objects.

    .EXAMPLE
        Get-ADAttributeAlias -ObjectClass Group

        Displays the attribute aliases available for Group objects.
    #>

    [CmdletBinding()]
    param (
        [ValidateSet('User', 'Computer', 'Group', 'ServiceAccount', 'Principal', 'Account')]
        [String]$ObjectClass = 'User'
    )

    $requestedType =  'AD{0}' -f $ObjectClass
    $namespace = 'Microsoft.ActiveDirectory.Management'

    if ($instanceType = '{0}.{1}' -f $namespace, $requestedType -as [Type]) {
        $type = '{0}.Commands.{1}Factory[{0}.{1}]' -f @(
            $namespace
            $requestedType
        ) -as [Type]

        do {
            $nestedTypeName = '{0}PropertyMap' -f $type.Name -replace 'Factory.+\d'

            if ($nestedType = $type.GetNestedType($nestedTypeName, 'NonPublic,Static')) {
                $nestedType = $nestedType.MakeGenericType($instanceType)
                foreach ($field in $nestedType.GetFields('Public, Static')) {
                    $field.GetValue($null)
                }
            }

            $type = $type.BaseType
        } until ($type.BaseType -eq [Object])
    } else {
        Write-Warning ('Cannot find type for {0}' -f $ObjectClass) 
    }
}