joshuakgoldberg/unist-util-visit

When you write something in Markdown, a tool converts your text into a tree-like structure where each piece, a paragraph, a bold word, a code snippet, becomes a "node." The unist-util-visit package gives developers a simple way to walk through that tree, stopping at each node along the way. It's essentially a tour guide for structured text content. The core idea is straightforward: you hand the tool your tree and a function. It then walks through every node in order and runs your function on each one. Your function can just look at the node (to find something specific, for instance), or it can change it entirely. As it walks, the tool gives your function context about where it is, the current node, its position (index) among its siblings, and its parent node. You can also filter which nodes to stop at, so you don't have to inspect every single one. Developers use this when they need to find, read, or modify specific parts of a document. For example, if you have a Markdown file and want to find every piece of plain text, you could use this tool to visit only "text" nodes and log their contents. It's the kind of utility you'd reach for when building something like a spellchecker, a tool that rewrites links, or a linter that flags problematic formatting, anything where you need to scan or transform structured content piece by piece. One thing worth noting is the fine-grained control it gives you over the walking process. At any point, your function can tell the tool to keep going as normal, stop entirely (useful once you've found what you need), or skip the children of the current node. This means you can bail out early or skip deeply nested sections you don't care about, which is helpful for performance when dealing with large documents. The project also includes TypeScript types, which helps developers catch mistakes before they run their code.