Getting Azure AD Users by a Filterable Attribute

GetAzureADUserByAnAttribute.ps1

function Get-AzureADUserByAttribute
{
    <#
.SYNOPSIS
    Get Azure AD users by an arbitrary filterable attribute, such as MailNickName.
.DESCRIPTION
    Get Azure AD users by an arbitrary filterable attribute, such as MailNickName.
.EXAMPLE

    $list = Import-CSV .\TempTestUsers.csv
    $list | Get-AzureADUserByAttribute -Attribute MailNickName -UserListAttribute ID

    The csv file imported above has a column named ID which contains a value which will match a user's mailnickname in Azure AD.
    The actual attribute being compared in Azure AD is MailNickName
    This retrieves any matching users from the list from Azure AD where ID = MailNickName and passes them as output.  Any errors that occur are also output.

.EXAMPLE

    $list = Import-CSV .\TempTestUsers.csv
    Get-AzureADUserByAttribute -Attribute MailNickName -UserListAttribute ID -UserList $list

    The csv file imported above has a column named ID which contains a value which will match a user's mailnickname in Azure AD.
    The actual attribute being compared in Azure AD is MailNickName
    This retrieves any matching users from the list from Azure AD where ID = MailNickName and passes them as output.  Any errors that occur are also output.

.EXAMPLE

    $Mailboxes = @(Get-Mailbox -identity Mike)
    Get-AzureADUserByAttribute -Attribute MailNickName -UserListAttribute Alias -UserList $Mailboxes

    Retrieve mailbox(es) from Microsoft Exchange.
    The actual attribute being compared in Azure AD is MailNickName.  The Exchange Mailboxes have an attribute which should match (Alias).
    This retrieves any matching users from the mailboxes from Azure AD where ID = MailNickName and passes them as output.  Any errors that occur are also output.

.PARAMETER Attribute
The Azure AD Filterable Attribute that will be compared with the specified UserListAttribute. The comparison operator used is 'eq', an exact, not case sensitive match.

.PARAMETER UserListAttribute
The colunm/property/attribute from the UserList object(s) which will be compared to the Azure AD filterable Attribute. The comparison operator used is 'eq', an exact, not case sensitive match.

#>
    [cmdletbinding()]
    param(
        [parameter(Mandatory, ValueFromPipeline)]
        [psobject[]]$UserList #Any object representation of one or more users with attribute values you want to search Azure AD with.
        ,
        [parameter()]
        [string]$Attribute
        ,
        [parameter()]
        [string]$UserListAttribute
    )
    begin
    {
        if ($null -eq $(Get-AzureADCurrentSessionInfo))
        {
            throw('Run Connect-AzureAD before running this script')
        }
    }
    process
    {
        foreach ($u in $UserList)
        {
            switch ([string]::IsNullOrWhiteSpace($UserListAttribute))
            {
                $true
                { Get-AzureADUser -Filter "$Attribute eq '$u'" }
                $false
                { Get-AzureADUser -Filter "$Attribute eq '$($u.$UserListAttribute)'" }
            }

        }
    }
}