Support "browser" deep module references

[justinbmeyer]

I would like to support re-pathing "deep" directory references with the browser config. This was brought up here in node-browser-resolve. And it was suggested here that the changes partly belong in node-resolve.

To make this change, I will need to change node-resolve to make a better attempt to find the package.json and opts hook that supports repathing.

loadAsDirectory, given a path like x = "../node_modules/foo/bar" will look for package.json in "../node_modules/package.json".

If given a path without node_modules like: x = "/Users/justin/dev/project/foo/bar", it will look for package.json in each folder until it finds it.

If a "deep" module reference is being resolved, a package.json is found, and an opts.pathFilter is found, opts.pathFinder(pkg, x, relativeX) will be called where:

• pkg - the package data
• x - the moduleId attempted to be resolved
• relativeX - the moduleId path relative to the package.json location.

If opts.pathFilter returns a value, the returned value will be joined from the package.json location and passed to loadAsFile. Otherwise, x will be used with loadAsFile.

Example:

loadAsDirectory("/Users/justin/dev/project/foo/bar") 
  opts.pathFilter(pkg, "/Users/justin/dev/project/foo/bar", "./foo/bar") //-> "./browser/foo/bar"
  loadAsFile("/Users/justin/dev/project/browser/foo/bar", pkg)

Thoughts on this, the changes, and the choice of the pathFilter name and arguments? Thanks!

/cc @defunctzombie

[justinbmeyer]

Actually, it seems that loadAsFile will need this behavior too.

[ljharb]

This seems addressed.