Properly resolve absolute path of exposed module.

[jmm]

The change in #1033 is flawed. And the test coverage for requires is inadequate.

See #1039 (part 1). A broken bundle is generated when doing something like...

// bundle.js
browserify('./src/a')
  .require('./src/b');

// src/a.js
require('./b');

// src/b.js
// I'm the file being required

...because the code in #1033 essentially does...

this._expose[row.id] = '/somedir/src/b';

...which leads to a mismatch here...

https://github.com/substack/deps-sort/blob/c61e515015a0f8392c1b07530877084b6c411cb7/index.js#L72

...because there should be an entry index['/somedir/src/b.js'], but instead there's index['/somedir/src/b'].

I'm not 100% sure this pull request completely and correctly solves the problem for all cases, but it does solve it for the scenario in #1039 and is a step in the right direction. That this apparently used to work (according to @gasi in #1033) and that #1033 was merged as a fix underscores the need for better and more comprehensive tests around this functionality.

[jmm]

Here's an example of a test that currently fails:

jmm/node-browserify@ae9aedb

[ghost]

Merged in 8.1.1 with an asynchronous version. Thanks for the patch!

[jmm]

@substack Thanks! I started working on an async version after I submitted this pull request and I think it was shaping up similar to what you did (although I've only glanced at that so far) -- I was mimicking the pattern used for adding transforms -- but then I realized I think there's an even better solution, since the paths are already being resolved later on. I'll flesh that out a bit more and submit a pull request so you can see what you think.