PowerShell script to retrieve lists of classes and ids from a html string and output a CSS skeleton for them

get-classes-and-ids.ps1

[System.Text.RegularExpressions.MatchCollection]$classesAndIds = [regex]::Matches($html, 'class="(?<Classes>[^"]+)"|id="(?<Id>[^"]+)"')

$classes = [System.Collections.Generic.HashSet[string]]::new()
$ids = [System.Collections.Generic.HashSet[string]]::new()

$classesAndIds.Captures.Groups.ForEach{
    if ($_.Name -eq 'Classes') {
        $_.Value -split '[\s\r\n]' -replace '\{/?block:[^}]\}' |
            Where-Object {$_} |
            ForEach-Object {
                $classes.Add(".$_ {`n`n}`n`n") > $null
            }
    }
    elseif ($_.Name -eq 'Id') {
        $ids.Add("#$($_.Value) {`n`n}`n`n")
    }
}

@(
    $ids
    $classes
) -join "`n"