fix: remove the unmaintained mkdirp dependency

[shinnn]

206b83f introduced the mkdirp dependency to c8, but I'm very opposed to use such a no longer maintained package.

For feature detection, we can check the existence of fs.promises which is only available in Node.js >= 10.0.0.

Checklist

• npm test, tests passing

[coveralls]

Pull Request Test Coverage Report for Build 261

• 9 of 9 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.04%) to 96.709%

---

Totals
Change from base Build 253:	0.04%
Covered Lines:	444
Relevant Lines:	453

---

💛 - Coveralls

[bcoe]

@shinnn the problem isn't the lack of promisify, it's the fact that recursive doesn't work on older Node.js versions, leading to this bug:

Benjamins-MBP-2:c8 benjamincoe$ ./bin/c8.js node foo.js
(node:15352) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 2): Error: ENOENT: no such file or directory, scandir './coverage/tmp'
(node:15352) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

Perhaps you could either:

• check to see if the directory actually exists, and exit with 0 and warn if it doesn't after attempting to create it.
• or switch to using make-dir which is maintained, and falls back to recursive if it's available.

[bcoe]

see my note; could we compromise and use make-dir which falls back to mkdir recursive.

[shinnn]

Actually 491aebb doesn't work properly on Node.js 8, but

it's the fact that recursive doesn't work on older Node.js versions

is not correct. The real problem is that c8 still tries to output coverage reports even though NODE_V8_COVERAGE is not supported. Check the stack trace.

(node:82468) UnhandledPromiseRejectionWarning: Error: ENOENT: no such file or directory, scandir './coverage/tmp'
    at fs.readdirSync (fs.js:904:18)
    at Report._loadReports (/Users/shinnn/c8/lib/report.js:124:19)

[shinnn]

I added a new commit 85b9beb which suppresses the error mentioned in #91 (comment).

@bcoe Can you pull the up-to-date branch and try it again with Node.js 8?

[bcoe]

maybe just pull in semver a dependency and:

if (semver.lt('10.12.0', process.version)) {
  console.warn('native test coverage was not added to V8 until 10.12.0')
  foreground(hideInstrumenterArgs(argv))
  return
}

that way we're not relying on util.promisify not being back-ported.

👍 thanks for your work on this; I'll be back a bit later today.

[shinnn]

that way we're not relying on util.promisify not being back-ported.

To be accurate, the API used for feature detection here is not util.promisify but fs.promises.

I can hardly imagine the Node.js team decides to back-port fs.promises to the maintenance LTS version.

[bcoe]

perhaps just add a comment then:

// fs.promises was not added until Node v10.0.0, if it doesn't
// exist, assume we're Node v8.x and skip coverage.

[shinnn]

938a463

[bcoe]

@shinnn thank you!

[shinnn]

@bcoe No problem. Thanks for the review.