chore(bin): rewrite to async I/O

- Replace mkdirp with the new fs.mkdir with `recursive` option
- Rewrite all top level IO to async (mkdir and rimraf)

Remaining work: to rewrite lib/*.js to async I/O

Ref: bcoe#9

bin/c8.js

@@ -1,8 +1,10 @@
 #!/usr/bin/env node
 'use strict'
 
+const fs = require('fs')
+const util = require('util')
+
 const foreground = require('foreground-child')
-const mkdirp = require('mkdirp')
 const report = require('../lib/report')
 const rimraf = require('rimraf')
 const {
@@ -14,20 +16,7 @@ const {
 const instrumenterArgs = hideInstrumenteeArgs()
 let argv = yargs.parse(instrumenterArgs)
 
-if (argv._[0] === 'report') {
-  argv = yargs.parse(process.argv) // support flag arguments after "report".
-  outputReport()
-} else {
-  if (argv.clean) {
-    rimraf.sync(argv.tempDirectory)
-    mkdirp.sync(argv.tempDirectory)
-  }
-  process.env.NODE_V8_COVERAGE = argv.tempDirectory
-
-  foreground(hideInstrumenterArgs(argv), () => {
-    outputReport()
-  })
-}
+const _p = util.promisify
 
 function outputReport () {
   report({
@@ -40,3 +29,20 @@ function outputReport () {
     omitRelative: argv.omitRelative
   })
 }
+
+(async function run () {
+  if (argv._[0] === 'report') {
+    argv = yargs.parse(process.argv) // support flag arguments after "report".
+    outputReport()
+  } else {
+    if (argv.clean) {
+      await _p(rimraf)(argv.tempDirectory)
+      await _p(fs.mkdir)(argv.tempDirectory, { recursive: true })
+    }
+    process.env.NODE_V8_COVERAGE = argv.tempDirectory
+
+    foreground(hideInstrumenterArgs(argv), () => {
+      outputReport()
+    })
+  }
+})()

package.json

@@ -37,7 +37,6 @@
     "istanbul-lib-coverage": "^2.0.1",
     "istanbul-lib-report": "^2.0.1",
     "istanbul-reports": "^2.0.0",
-    "mkdirp": "^0.5.1",
     "rimraf": "^2.6.2",
     "test-exclude": "^5.0.0",
     "uuid": "^3.3.2",

test/integration.js.snap

@@ -8,9 +8,9 @@ second
 --------------------|----------|----------|----------|----------|-------------------|
 File                |  % Stmts | % Branch |  % Funcs |  % Lines | Uncovered Line #s |
 --------------------|----------|----------|----------|----------|-------------------|
-All files           |     92.5 |    69.23 |        0 |     92.5 |                   |
- bin                |    83.72 |    57.14 |      100 |    83.72 |                   |
-  c8.js             |    83.72 |    57.14 |      100 |    83.72 |... 22,40,41,42,43 |
+All files           |    93.01 |    69.81 |        0 |    93.01 |                   |
+ bin                |    87.76 |     62.5 |      100 |    87.76 |                   |
+  c8.js             |    87.76 |     62.5 |      100 |    87.76 | 35,39,46,47,48,49 |
  lib                |    93.71 |    62.96 |      100 |    93.71 |                   |
   parse-args.js     |    97.47 |    44.44 |      100 |    97.47 |             55,56 |
   report.js         |    90.63 |    72.22 |      100 |    90.63 |... 70,71,85,86,87 |