Container Nesting (autoNesting)

The CommonMark Challenge

In standard Markdown (markdown-it-container), an opening container (:::) closes at the first closing fence with at least as many colons. When nesting containers with the same fence level, this causes premature closures:

::: note-box
Outer text.
::: grammar-box
Inner box content
:::
This was intended to be inside note-box, but the container was already closed!
:::

The Solution

markdown-it-extensible includes autoNesting, which runs as a pre-parse rule. It scans the source text before rendering and automatically normalizes the colon fence depth.

The snippet above is normalized automatically and transparently to:

:::: note-box
Outer text.
::: grammar-box
Inner box content
:::
This was intended to be inside note-box, but the container was already closed!
::::

Disabling & Configuration

autoNesting is enabled by default. If you wish to disable it for performance or compatibility reasons, configure options:

md.use(extensiblePlugin, { autoNesting: false });

To automatically append missing closing fences at the end of the document:

md.use(extensiblePlugin, { 
  autoNesting: { closeUnclosed: true } 
});