$PSStyle polyfill forWindows PowerShell

PSStylePolyfillForWinPS.ps1

# $PSStyle polyfill for Windows PowerShell:
# When run on a PS v7.2+ system, generates source code for Windows PowerShell 
# that creates a nested ordered hashtable that mimics the v7.2+ $PSStyle object,
# albeit only with respect to the properties with general-purpose ANSI (VT) 
# escape sequences, such as $PSStyle.Italic and $PSStyle.Foreground.Yellow
#
# Simply copy and paste this snippet and execute it in a PowerShell 7.2+ session, 
# and it will output source code for Windows PowerShell that defines $PSStyle.
@"
if (`$null -eq `$PSStyle) {
  `$PSStyle = [ordered] @{}
  $(
      foreach ($p in $PSStyle.psobject.Properties.Name -notmatch '^(Foreground|Background|FileInfo|Formatting|OutputRendering|Progress)$') {
        "  `$PSStyle.$p = `"$($PSStyle.$p -replace "`e", '$([char]27)')`"`n"
      }
    foreach ($p in 'Foreground', 'Background') {
      "  `$PSStyle.$p = [ordered] @{}`n"
      foreach ($sp in $PSStyle.$p.psobject.Properties.Name) {
        "    `$PSStyle.$p.$sp = `"$($PSStyle.$p.$sp -replace "`e", '$([char]27)')`"`n"
      }
    }
  )
}
"@

PSStylePolyfillForWinPS_Result.ps1

# Running the above in PowerShell 7.4.0-preview.3 yields the following:

if ($null -eq $PSStyle) {
  $PSStyle = [ordered] @{}
    $PSStyle.Reset = "$([char]27)[0m"
   $PSStyle.BlinkOff = "$([char]27)[25m"
   $PSStyle.Blink = "$([char]27)[5m"
   $PSStyle.BoldOff = "$([char]27)[22m"
   $PSStyle.Bold = "$([char]27)[1m"
   $PSStyle.DimOff = "$([char]27)[22m"
   $PSStyle.Dim = "$([char]27)[2m"
   $PSStyle.Hidden = "$([char]27)[8m"
   $PSStyle.HiddenOff = "$([char]27)[28m"
   $PSStyle.Reverse = "$([char]27)[7m"
   $PSStyle.ReverseOff = "$([char]27)[27m"
   $PSStyle.ItalicOff = "$([char]27)[23m"
   $PSStyle.Italic = "$([char]27)[3m"
   $PSStyle.UnderlineOff = "$([char]27)[24m"
   $PSStyle.Underline = "$([char]27)[4m"
   $PSStyle.StrikethroughOff = "$([char]27)[29m"
   $PSStyle.Strikethrough = "$([char]27)[9m"
   $PSStyle.Foreground = [ordered] @{}
     $PSStyle.Foreground.Black = "$([char]27)[30m"
     $PSStyle.Foreground.Red = "$([char]27)[31m"
     $PSStyle.Foreground.Green = "$([char]27)[32m"
     $PSStyle.Foreground.Yellow = "$([char]27)[33m"
     $PSStyle.Foreground.Blue = "$([char]27)[34m"
     $PSStyle.Foreground.Magenta = "$([char]27)[35m"
     $PSStyle.Foreground.Cyan = "$([char]27)[36m"
     $PSStyle.Foreground.White = "$([char]27)[37m"
     $PSStyle.Foreground.BrightBlack = "$([char]27)[90m"
     $PSStyle.Foreground.BrightRed = "$([char]27)[91m"
     $PSStyle.Foreground.BrightGreen = "$([char]27)[92m"
     $PSStyle.Foreground.BrightYellow = "$([char]27)[93m"
     $PSStyle.Foreground.BrightBlue = "$([char]27)[94m"
     $PSStyle.Foreground.BrightMagenta = "$([char]27)[95m"
     $PSStyle.Foreground.BrightCyan = "$([char]27)[96m"
     $PSStyle.Foreground.BrightWhite = "$([char]27)[97m"
   $PSStyle.Background = [ordered] @{}
     $PSStyle.Background.Black = "$([char]27)[40m"
     $PSStyle.Background.Red = "$([char]27)[41m"
     $PSStyle.Background.Green = "$([char]27)[42m"
     $PSStyle.Background.Yellow = "$([char]27)[43m"
     $PSStyle.Background.Blue = "$([char]27)[44m"
     $PSStyle.Background.Magenta = "$([char]27)[45m"
     $PSStyle.Background.Cyan = "$([char]27)[46m"
     $PSStyle.Background.White = "$([char]27)[47m"
     $PSStyle.Background.BrightBlack = "$([char]27)[100m"
     $PSStyle.Background.BrightRed = "$([char]27)[101m"
     $PSStyle.Background.BrightGreen = "$([char]27)[102m"
     $PSStyle.Background.BrightYellow = "$([char]27)[103m"
     $PSStyle.Background.BrightBlue = "$([char]27)[104m"
     $PSStyle.Background.BrightMagenta = "$([char]27)[105m"
     $PSStyle.Background.BrightCyan = "$([char]27)[106m"
     $PSStyle.Background.BrightWhite = "$([char]27)[107m"

}