internal/functions/resolve/Resolve-SubscribedSku.ps1

function Resolve-SubscribedSku
{
    [CmdletBinding()]
    Param (
        [Parameter(Mandatory = $true)]
        [string] $InputReference,
        [switch] $DontFailIfNotExisting,
        [switch] $Expand, # Return object { skuId, skuPartNumber, servicePlans }
        [switch] $DisplayName, # Return skuPartNumber
        [System.Management.Automation.PSCmdlet]
        $Cmdlet = $PSCmdlet
    )
    
    begin {
        $InputReference = Resolve-String -Text $InputReference
    }
    process
    {            
        try {
            if (-Not $script:cache["allSubscribedSkus"]) {
                $script:cache["allSubscribedSkus"] = (Invoke-MgGraphRequest -Method GET -Uri "$script:graphBaseUrl/subscribedSkus").Value `
                                            | Select-Object @{n = "id"; e = {$_["id"]}}, @{n = "skuPartNumber"; e = {$_["skuPartNumber"]}},
                                                            @{n = "servicePlans"; e = {$_["servicePlans"]}}, @{n = "skuId"; e = {$_["skuId"]}}
            }

            if ($InputReference -match $script:guidRegex) { $sku = $script:cache["allSubscribedSkus"] | Where-Object { $_.skuId -eq $InputReference } | Select-Object -First 1 }
            else { $sku = $script:cache["allSubscribedSkus"] | Where-Object { $_.skuPartNumber -eq $InputReference } | Select-Object -First 1 }
            if (-Not $sku -and -Not $DontFailIfNotExisting) { throw "Cannot find subscribedSkus $InputReference" } elseif (-Not $sku -and $DontFailIfNotExisting) { return $InputReference }
            if ($sku.count -gt 1) { throw "Got multiple subscribedSkus for $InputReference" }
            if (-not $Expand) { if ($DisplayName) { return ($sku.skuPartNumber) } return $sku.skuId }
            return [pscustomobject]@{ skuId=$sku.skuId; skuPartNumber=$sku.skuPartNumber; servicePlans=$sku.servicePlans }
        }
        catch {
            Write-PSFMessage -Level Warning -Message ("Cannot resolve SubscribedSku resource for input '{0}'. Searched tenant & desired configuration. Error: {1}" -f $InputReference,$_.Exception.Message) -Tag 'failed' -ErrorRecord $_
            $Cmdlet.ThrowTerminatingError($_)                
        }            
    }
}