detect up a directory then down the same directory

I have a structure like:

```
/ham/egg/chips/index.js
/ham/egg/foo.js
```

then in /ham/egg/chips/index.js I sometimes have code that accidental ends up like:

``` js
import x from '../../egg/foo.js'
```

but I'd much rather it be:

``` js
import x from '../foo.js'
```
