internal/functions/validate/Validate-AccessReviewReviewers.ps1

function Validate-AccessReviewReviewers
{
    <#
        .SYNOPSIS
            Validates reviewers of access reviews

        .PARAMETER reference
            The id, displayName, userPrincipalName or mailNickname of the referenced resource.
    #>

    [CmdletBinding()]
    Param (
        [Parameter(ParameterSetName = "Default")]
        [string] $reference,
        [ValidateSet("singleUser", "groupMembers")]
        [string] $type = "singleUser",
        [System.Management.Automation.PSCmdlet]
        $Cmdlet = $PSCmdlet
    )
    
    begin {
        $parentResourceName = "accessReviews"
    }
    
    process
    {
        if (Test-PSFFunctionInterrupt) { return }                

        $hashtable = @{
            "queryType" = "MicrosoftGraph"
            "queryRoot" = $null
        }

        switch ($type) {
            "singleUser" {
                $id = Resolve-User -InputReference $reference -Cmdlet $PSCmdlet
                $hashtable["query"] = "/v1.0/users/$($id)"
            }
            "groupMembers" {
                $id = Resolve-Group -InputReference $reference -Cmdlet $PSCmdlet
                $hashtable["query"] = "/v1.0/groups/$($id)/transitiveMembers/microsoft.graph.user"
            }
        }
    }
    end
    {
        $hashtable
    }
}