leverage import.meta.resolve to support import maps generation and accurate node_modules resolution when building

[thescientist13]

Type of Change

• New Feature Request
• Documentation / Website
• Improvement / Suggestion
• Bug
• Other (please clarify below)

Summary

Coming out #674 for #570 which lets NodeJS do node_modules resolution for us by using require.resolve, one take away was that once NodeJS supports import.meta.resolve, we can use that instead.

Preview implementation for reference - https://github.com/ProjectEvergreen/greenwood/blob/v0.29.0/packages/cli/src/lib/node-modules-utils.js#L13

Details

In plugin-node-modules, we have a couple functions that are doing the work of finding entry points and building up an import map for the user, primarily for development purposes.

• getPackageEntryPoint - as the name implies, it uses package.json to find the right entry point, but now that we are able to get this from require.resolve, do we sill need this at all?
• walkModule - given an entry point, this walks through all the import and export statements to add to the overall importMap. I wonder though if export maps invalidates the need for this? In theory, wouldn't dependencies in package.json / main or exports fields be able to provide all the information we need?

In addition, we might not want to be hardcoding process.cwd() in walkPackageJson
https://github.com/ProjectEvergreen/greenwood/blob/master/packages/cli/src/plugins/resource/plugin-node-modules.js#L110

const walkPackageJson = async (packageJson = {}) => {

  for (const dependency of Object.keys(packageJson.dependencies || {})) {
    const dependencyPackageRootPath = path.join(process.cwd(), './node_modules', dependency);
    const dependencyPackageJsonPath = path.join(dependencyPackageRootPath, 'package.json');
    ...
  }
}

[thescientist13]

So far this is working nice, but seeing a minor issue regarding a package that has an empty main field in package.json, but can probably work around it
https://github.com/thescientist13/import-meta-resolve-demo

[thescientist13]

Looks like this issue may help things in terms of getting to a package root, but will probably have to try / catch my through this in the meantime, and would help avoid the edge case with @types/trusted-types identified above