hast VS unist-util-visit

contentlayer uses remark to parse the markdown in an mdast. We can now use remark plugins to modify the mdast. Then rehype comes into play and converts the mdast into a hast. rehype plugins can now modify the hast. Finally the hast is converted into react components.

remark-rehype translates the mdast structure into a Hypertext Abstract Syntax Tree (hast) structure, also composed of unist nodes.

We have to pass hast elements thought. If you want to read more about hast elements, check out this documentation link.

Is it so hard to accept that a tool or app could compile a html document into some intermediate form and then use that to internally construct a DOM representation, maybe out of a cache?

Although we are building a custom table of contents, we won't have to write everything from scratch. To separate the Markdown/MDX content from the front matter, we'll use the Gray-matter package. It is optional in case you don't have front matter in your Markdown files. To process the Markdown itself, we'll use the Remark package. We'll also need the unist-util-visit package for traversing node trees and mdast-util-to-string for getting the text content of a node.

For this example, we will use unist-util-visit to recursively inspect all the image nodes, and unist-util-generated to ensure we are not inspecting nodes that we have generated ourselves and do not belong to the doc.md.