Format-Bytes: My Version

Format-Bytes.ps1

filter Format-Bytes {
    if ($_ -is [ValueType]) {
        $x = if (0 -ne $_) { 
                [Math]::Min([int][Math]::Truncate([Math]::Log([Math]::Abs($_), 1kb)), 8)
            } else {
                0
            }
        if ($x -eq 0) {
            "$_ B"
        } else {
            "{0:N2} $('KMGTPEZY'[$x - 1])B" -f ($_ / [Math]::Pow(1kb, $x))
        }
    } else {
        $_ # return the input because it could not be processed
    }
}

This is my take on the many variations of Format-Bytes function. I have applied it as a filter, which means it works exclusively with pipelines.

1tb | Format-Bytes # returns '1.00 TB'
1023 | Format-Bytes # returns '1023 B'
1024, -1073741824000000000pb | Format-Bytes # returns '1.00 KB', '-1,000,000,000.00 YB'

If NULL is input, NULL will be returned.