https://constantinekokkinos.com/articles/210/generating-tables-of-contents-for-github-projects-with-powershell

generating-tables-of-contents-for-github-projects-with-powershell.ps1

#

Set-StrictMode -Version 2
$ErrorActionPreference = "Stop"
function Convert-StringToMarkdownTableOfContents {
    param ([string]$MarkdownDocument)

    $nl = [System.Environment]::NewLine
    $TOC = "## Table Of Contents$nl$nl"

    foreach ($line in $MarkdownDocument.Split( $nl )){
        if ($line -match "^(#+)\s(.*)$") {
            $Count = $Matches[1].Length
            $Content = $($Matches[2])

            $EncodedContent = ($Content -replace " ",'-').ToLower()

            if ($Count -eq 1){
                $TOC += "- [$Content](#$EncodedContent)$nl"
            }
            else {
                $TOC += "$("  " * $Count)* [$Content](#$EncodedContent)$nl"
            }

            $MarkdownDocument = $MarkdownDocument -replace "(($line)\w*)",$(
                '<a href = "#'+ $EncodedContent +'"></a>' +
                $nl +
                $line
            )
        }
    }

    return $TOC + $nl + $MarkdownDocument
}
Set-Alias -Value "Convert-StringToMarkdownTableOfContents" -Name "Convert-StringToMdToc"

$MdExamples = @(

@'
# Initial Idea

Let''s generate a table of contents for a Github flavored Markdown document in PowerShell (because nobody else seems to have.)

## Clairfying Our Requirements

After talking with Claudio, he didn''t just want a TOC for a particular markdown file (though that''s nice), but he also wanted a TOC for a set of files in a folder.
I decided to do the first one, and it looks like Claudio just finished the second.

I did some googling and found that Github flavored markdown supports a special form of anchor linking as it isn''t supported in vanilla MD.
I also found that beyond this there wasn't a good anchor link MD shortcut, so I took this tact (which cares more about readability than speed or length.)

You can use the function below, which was also run on this blog post to generate itself.

## The Code

``` PowerShell
function Convert-StringToMarkdownTableOfContents {
    param ([string]$MarkdownDocument)

    $nl = [System.Environment]::NewLine
    $TOC = "## Table Of Contents$nl$nl"

    foreach ($line in $MarkdownDocument.Split( $nl )){
        if ($line -match "^(#+)\s(.*)$") {
            $Count = $Matches[1].Length
            $Content = $($Matches[2])

            $EncodedContent = ($Content -replace " ",''-'').ToLower()

            if ($Count -eq 1){
                $TOC += "- [$Content](#$EncodedContent)$nl"
            }
            else {
                $TOC += "$("  " * $Count)* [$Content](#$EncodedContent)$nl"
            }

            $MarkdownDocument = $MarkdownDocument -replace "(($line)\w*)",$(
                ''<a href = "#'+ $EncodedContent +''"></a>'' +
                $nl +
                $line
            )
        }
    }
    return $TOC + $nl + $MarkdownDocument
}
```

## Special Thanks

Special thanks to [Cláudio Silva](https://claudioessilva.eu/) (PowerShell MVP) for giving me this fun idea!

'@

)

foreach ($eg in $MdExamples){
    Convert-StringToMarkdownTableOfContents -MarkdownDocument $eg
}