Adding a table of contents becomes very easy with Daux.io

Manual

Add [TOC] anywhere in your document and it will be replaced by a table of contents.

You can add it more than once in a page.

Automatic

Works only for html mode

A table of contents can be added automatically to all pages.

If [TOC] isn't present it will add it at the beginning of the page.

You can enable this feature in your configuration

{
    "html": {
        "auto_toc": true
    }
}