ConvertTo-Markdown.ps1

<#
.Synopsis
   Converts a PowerShell object to a Markdown table.
.EXAMPLE
   $data | ConvertTo-Markdown
.EXAMPLE
   ConvertTo-Markdown($data)
#>
Function ConvertTo-Markdown {
    [CmdletBinding()]
    [OutputType([string])]
    Param (
        [Parameter(
            Mandatory = $true,
            Position = 0,
            ValueFromPipeline = $true
        )]
        [PSObject[]]$collection
    )

    Begin {
        $items = @()
        $columns = @{}
    }

    Process {
        ForEach($item in $collection) {
            $items += $item

            $item.PSObject.Properties | %{
                if(-not $columns.ContainsKey($_.Name) -or $columns[$_.Name] -lt $_.Value.ToString().Length) {
                    $columns[$_.Name] = $_.Value.ToString().Length
                }
            }
        }
    }

    End {
        ForEach($key in $($columns.Keys)) {
            $columns[$key] = [Math]::Max($columns[$key], $key.Length)
        }

        $header = @()
        ForEach($key in $columns.Keys) {
            $header += ('{0,-' + $columns[$key] + '}') -f $key
        }
        $header -join ' | '

        $separator = @()
        ForEach($key in $columns.Keys) {
            $separator += '-' * $columns[$key]
        }
        $separator -join ' | '

        ForEach($item in $items) {
            $values = @()
            ForEach($key in $columns.Keys) {
                $values += ('{0,-' + $columns[$key] + '}') -f $item.($key)
            }
            $values -join ' | '
        }
    }
}