eliminate baseDir and support mounting, close #235

[panlina]

As addressed in #235 , baseDir is eliminated and mounting is supported to achieve the same purpose.

Instead of
app.use(ecstatic({.., baseDir: "a"}));,
we now do:
app.use('/a', ecstatic({..}));.

[codecov-io]

Codecov Report

Merging #237 into master will decrease coverage by 0.46%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master     #237      +/-   ##
==========================================
- Coverage   75.41%   74.95%   -0.47%     
==========================================
  Files           9        9              
  Lines         541      539       -2     
  Branches      125      127       +2     
==========================================
- Hits          408      404       -4     
  Misses         46       46              
- Partials       87       89       +2

Impacted Files	Coverage Δ
lib/ecstatic/opts.js	77.96% <ø> (ø)	⬆️
lib/ecstatic.js	72.5% <0%> (-0.53%)	⬇️
lib/ecstatic/show-dir/index.js	73.41% <0%> (-1.59%)	⬇️

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[panlina]

@jfhbrook The codecov check fails. Does that mean I need add tests? I'm not familiar with coverage tools and how they count. You can review my changes and tell me if there's anything I need to do.

[imcuttle]

@panlina I guess you do not need the complex processing,

Just wrap ecstatic simply by #235 (comment)

[panlina]

@imcuttle It's not "complex processing". It's simplification. 😄 . I saw your solution. It may work but that's a temporary solution as you said.

[jfhbrook]

Forgive my thread necromancy!

My concern with this PR as it stands is that a lot of people use this module outside the context of ecstatic, where this flag is actually pretty useful.

Unfortunately I don't use express very often and certainly don't use this module with express! so I don't actually understand the desired behavior with express that well or why basedir breaks it. Is there a way to get this behavior without removing the baseDir option?

[jfhbrook]

Something that might be helpful for me is breaking tests for the behavior in express - this would give me a spec to work against.

[panlina]

Good to see you back after months!

Actually I changed my mind after that. It's better to keep it not relying on a hosting framework as since it's born.

Thank you for taking care of this PR. Now you can close it.