• mdx-bundler version: 10.0.3
• node version: 18.8.0, 18.14.1, 20.12.1
• npm version: 8.18.0, 9.5.0, 10.5.0
• esbuild version: 0.19.12, 0.23.1
• @esbuild-plugins/node-resolve version: 0.2.2

Relevant code or config

const result = await bundleMdx({
  file: "c:/project/index-c.mdx",
  cwd: "c:/project",
});

// c:/project/index-c.mdx

import packageC from "package-c";

<span>{packageC}</span>

I have identified that usage of basedir in NodeResolvePlugin causes the incorrect module resolution to occur for nested node_modules.

https://github.com/kentcdodds/mdx-bundler/pull/68/files#diff-bfe9874d239014961b1ae4e89875a6155667db834a410aaaa2ebe3cf89820556R149

What you did:

Attempt to bundle a component using package (package-a) with 2 different versions, imagine the node_modules structure like this

project
├── index-b.js
├── index-c.js
└── node_modules
    ├── package-a (1.0.0)
    │   ├── a.js
    │   └── package.json
    ├── package-b
    │   ├── b.js
    │   └── package.json
    └── package-c
        ├── c.js
        ├── node_modules
        │   └── package-a (2.0.0)
        │       ├── a.js
        │       └── package.json
        └── package.json

* exact version doesn't matter here, only the folder structure matter

• index-b imports package-b imports package-a
  • package-a should resolve to node_modules/package-a/a.js
• index-c imports package-c imports package-a
  • package-a should resolve to node_modules/package-c/node_modules/package-a/a.js

What happened:

The incorrect module is resolved.
mdx-bundler always resolve module at ${process.cwd()}/node_modules, breaking NodeJS's / ESBuild node module resolution logic.

• index-b imports package-b imports package-a
  • package-a resolved to node_modules/package-a/a.js
• index-c imports package-c imports package-a
  • package-a resolved to node_modules/package-a/a.js <-- ❌ incorrect resolution

Reference:

• esbuild - implements NodeJS module resolution

  ... implemented esbuild's path resolution by following node's own documentation ...
  - node resolution algorithm with NODE_PATH resolves in wrong order evanw/esbuild#1117 (comment)

• NodeJS module resolution

  - https://nodejs.org/docs/latest-v20.x/api/modules.html#loading-from-node_modules-folders

• @esbuild-plugins/node-resolve - by default follow NodeJS module resolution if basedir is not passed, and start looking for node_modules from the caller's module

  var basedir = opts.basedir || path.dirname(caller());

  basedir is default to the directory of the caller module when not provided

  - https://github.com/browserify/resolve/blob/v1.22.8/lib/async.js#L107

Reproduction repository:

A basic reproduce repo is created to demonstrate this point using only esbuild and @esbuild-plugins/node-resolve

https://github.com/amoshydra/repro-kentcdodds-mdx-bundler/tree/repro-issue-233

Test setup

build.mjs contains 3 setup:

• esbuild without plugin
• esbuild with @esbuild-plugins/node-resolve using default option
• esbuild with @esbuild-plugins/node-resolve passing project's working directory as basedir

Observation

dist folder contain the output for each build

• /dist/default/index-c.js
• /dist/resolve-default/index-c.js
• /dist/resolve-project-directory-as-basedir/index-c.js

Problem description:

mdx-bundler should follow NodeJS module resolution, but it does not.

Consequently, as we migrate our bundler from webpack/docz to mdx-bundler, we observe many of the packages failed to run due to incorrect module resolution

Suggested solution:

For the scope of my project, the following workarounds works for me:

• removing @esbuild-plugins/node-resolve, let esbuild perform the resolution
  (mdx-bundler cannot load md file if plugin is removed. mdx loads fine)
• passing our own @esbuild-plugins/node-resolve without the basedir option

  const result = await bundleMdx({
    file: "c:/project/document/document.mdx",
    cwd: "c:/project",
    esbuildOptions: (options) => {
      const nodeResolvePluginIndex = options.plugins.findIndex(({ name }) => name === "node-resolve");
      if (nodeResolvePluginIndex >= 0) {
        // replace original plugin with our own without `resolveOptions.basedir` configured
        options.plugins.splice(nodeResolvePluginIndex, 1, NodeResolvePlugin({
          extensions: [".ts", ".tsx", ".js", ".jsx"],
        }); 
      }
      return options;
    },
  });

Earlier, I wanted to suggest removing basedir.
However basedir appear to be added intentionally in #68. I have yet to look into what problem #68 is trying to solve