Async inside visit, or unist-util-visit-async package

[UlisseMini]

I'm trying to write a remarkRunCode function which replaces javascript code blocks with the run tag with their markdown export. Attached is my attempt at implementing this, the problem is at the await visit(tree, "code", async (node, index, parent) line, visit doesn't support async functions so this doesn't work. If I replace const module = await importInline(node.value) with const module = {markdown: "foo *bar* baz"} it works fine.

function remarkRunCode() {
  return async (tree, file) => {
    visit(tree, "code", async (node, index, parent) => {
      // check for "```js run", the stuff after the space is meta
      if (node.meta === "run") {
        const module = await importInline(node.value);
        const tree = unified().use(remarkParse).parse(module.markdown);
        parent.children.splice(index, 1, ...tree.children);
        console.log(parent.children.at(-1).children);

        // Skip traversing children of 'node' at 'index'
        return [SKIP, index];
      }
    });
  };
}

let cacheBusts = 0;
async function importInline(code) {
  let module;
  try {
    await fs.writeFile(".tmp.js", code);
    module = await import(`./.tmp.js?q=${++cacheBusts}`);
  } finally {
    await fs.remove(".tmp.js");
  }
  return module;
}

I fixed it by writing my own visit function (different semantics to the normal visit but it works for my usecase)

async function asyncVisit(node, test, callback, index, parent) {
  if (is(node, test)) {
    await callback(node, index, parent);
    // skip children by default, since code blocks don't have children
    // and that's what I'm using this for
  } else if (node.children) {
    for (const i in node.children) {
      await asyncVisit(node.children[i], test, callback, i, node);
    }
  }
}

But I feel this should be supported by default, either in unist-util-visit or some new package unist-util-visit-async.

[ChristianMurphy]

Crosslinking a previous version of this question: https://spectrum.chat/unified/syntax-tree/is-there-any-way-to-execute-async-work-when-visiting-a-node-in-unist-util-visit~28177826-628e-44e3-ac3e-0ffb53c195c6

[UlisseMini]

Nice! I thought about the Promise.all approach but not the way he did it, which is much nicer. Hopefully this question is more searchable since I couldn't find that spectrum thread.