How can I check if a string is null or empty in PowerShell?

Question

Is there a built-in IsNullOrEmpty-like function in order to check if a string is null or empty, in PowerShell?

I could not find it so far and if there i

Answer 1

# cases
$x = null
$x = ''
$x = ' '

# test
if ($x -and $x.trim()) {'not empty'} else {'empty'}
or
if ([string]::IsNullOrWhiteSpace($x)) {'empty'} else {'not empty'}