Noticed that we're checking more module paths than necessary. In
particular the module path array contains a couple of entries with a
duplicated `node_modules/node_modules` suffix.
```js
[
// ... more entries before here, where some also contain duplicate suffixes
"/Users/marvinhagemeister/dev/preact-render-to-string/node_modules/.deno/node_modules",
"/Users/marvinhagemeister/dev/preact-render-to-string/node_modules/node_modules", // <-- duplicate suffix
"/Users/marvinhagemeister/dev/preact-render-to-string/node_modules",
"/Users/marvinhagemeister/dev/node_modules",
"/Users/marvinhagemeister/node_modules",
"/Users/node_modules",
"/node_modules",
"/node_modules" // <-- duplicate entry
]
```
This was caused by a misunderstanding in how Rust's
[`Path::ends_with()`](https://doc.rust-lang.org/std/path/struct.Path.html#method.ends_with)
works. It's designed to match on whole path segments and the suffix
`/node_modules` is not that, except for the root entry. This meant that
our check for if the path already ended with `node_module` always
returned `false`. Removing the leading slash fixes that.
While we're at it, we can remove the last condition where we explicitly
added the root `/node_modules` entry since the while loop prior to that
takes care of it already.
This internal node hook is used by libraries such as `ts-node` when used
as a require hook `node -r ts-node/register`. That combination is often
used with test frameworks like `mocha` or `jasmine`.
We had a reference to `Module._preloadModules` in our code, but the
implementation was missing. While fixing this I also noticed that the
`fakeParent` module that we create internally always threw because of
the `pathDirname` check on the module id in the constructor of `Mdoule`.
So this code path was probably broken for a while.
```txt
✖ ERROR: Error: Empty filepath.
at pathDirname (ext:deno_node/01_require.js:245:11)
at new Module (ext:deno_node/01_require.js:446:15)
at Function.Module._resolveFilename (ext:deno_node/01_require.js:754:28)
at Function.resolve (ext:deno_node/01_require.js:1015:19)
```
