feat: make __coverage__ the default approach we advocate for ES2015 coverage (istanbuljs#268)

* feat: make nyc behave better when used with babel-plugin-__coverage__ (see istanbuljs#266)

* feat: abstract test include/exclude logic into its own module

* fix: add text-exclude dependency

* fix: should have instrumenters in files list

* fix: fix remapping issue with source-maps

* fix: typo was causing argument not to propagate

* docs: add section introducing __coverage__ for ES6/ES7

* docs: a couple small edits

Author: bcoe

README.md

@@ -60,6 +60,42 @@ of the pre-transpiled code. You'll have to configure your custom require hook
 to inline the source map in the transpiled code. For Babel that means setting
 the `sourceMaps` option to `inline`.
 
+## Use babel-plugin__coverage__ for Better ES6/ES7 Support
+
+[`babel-plugin-__coverage__`](https://github.com/dtinth/babel-plugin-__coverage__) can be used to enable better first-class ES6 support.
+
+1. enable the `__coverage__` plugin:
+
+  ```json
+    {
+      "babel": {
+        "presets": ["es2015"],
+        "plugins": ["__coverage__"]
+      }
+    }
+  ```
+
+2. disable nyc's instrumentation and source-maps:
+
+  ```json
+  {
+    "nyc": {
+      "include": [
+        "src/*.js"
+      ],
+      "require": [
+        "babel-register"
+      ],
+      "sourceMap": false,
+      "instrumenter": "./lib/instrumenters/noop"
+    }
+  }
+  ```
+
+That's all there is to it, better ES6 syntax highlighting awaits:
+
+<img width="500" src="screen2.png">
+
 ## Support For Custom File Extensions (.jsx, .es6)
 
 Supporting file extensions can be configured through either the configuration arguments or with the `nyc` config section in `package.json`.
@@ -249,8 +285,6 @@ That's all there is to it!
 [codecov](https://codecov.io/) is a great tool for adding
 coverage reports to your GitHub project, even viewing them inline on GitHub with a browser extension:
 
-![browser extension](https://d234q63orb21db.cloudfront.net/ad63907877249140772dff929ad1c340e424962a/media/images/next/extension.png)
-
 Here's how to get `nyc` integrated with codecov and travis-ci.org:
 
 1. add the codecov and nyc dependencies to your module:

bin/nyc.js

@@ -97,6 +97,16 @@ var yargs = require('yargs/yargs')(process.argv.slice(2))
     description: 'what % of statements must be covered?',
     global: true
   })
+  .option('source-map', {
+    default: true,
+    type: 'boolean',
+    description: 'should nyc detect and handle source maps?'
+  })
+  .option('instrumenter', {
+    default: './lib/instrumenters/istanbul',
+    type: 'string',
+    description: 'what library should be used to instrument coverage?'
+  })
   .help('h')
   .alias('h', 'help')
   .version()
@@ -125,15 +135,18 @@ if (argv._[0] === 'report') {
   var nyc = (new NYC({
     require: argv.require,
     include: argv.include,
-    exclude: argv.exclude
+    exclude: argv.exclude,
+    sourceMap: !!argv.sourceMap
   }))
   nyc.reset()
 
   if (argv.all) nyc.addAllFiles()
 
   var env = {
     NYC_CWD: process.cwd(),
-    NYC_CACHE: argv.cache ? 'enable' : 'disable'
+    NYC_CACHE: argv.cache ? 'enable' : 'disable',
+    NYC_SOURCE_MAP: argv.sourceMap ? 'enable' : 'disable',
+    NYC_INSTRUMENTER: argv.instrumenter
   }
   if (argv.require.length) {
     env.NYC_REQUIRE = argv.require.join(',')

bin/wrap.js

@@ -11,7 +11,9 @@ try {
   extension: process.env.NYC_EXTENSION ? process.env.NYC_EXTENSION.split(',') : [],
   exclude: process.env.NYC_EXCLUDE ? process.env.NYC_EXCLUDE.split(',') : [],
   include: process.env.NYC_INCLUDE ? process.env.NYC_INCLUDE.split(',') : [],
-  enableCache: process.env.NYC_CACHE === 'enable'
+  enableCache: process.env.NYC_CACHE === 'enable',
+  sourceMap: process.env.NYC_SOURCE_MAP === 'enable',
+  instrumenter: process.env.NYC_INSTRUMENTER
 })).wrap()
 
 sw.runMain()

index.js

@@ -1,7 +1,6 @@
 /* global __coverage__ */
 var fs = require('fs')
 var glob = require('glob')
-var micromatch = require('micromatch')
 var mkdirp = require('mkdirp')
 var Module = require('module')
 var appendTransform = require('append-transform')
@@ -17,7 +16,8 @@ var md5hex = require('md5-hex')
 var findCacheDir = require('find-cache-dir')
 var js = require('default-require-extensions/js')
 var pkgUp = require('pkg-up')
-var yargs = require('yargs/yargs')
+var testExclude = require('test-exclude')
+var yargs = require('yargs')
 
 /* istanbul ignore next */
 if (/index\.covered\.js$/.test(__filename)) {
@@ -30,29 +30,23 @@ function NYC (opts) {
   this._istanbul = config.istanbul
   this.subprocessBin = config.subprocessBin || path.resolve(__dirname, './bin/nyc.js')
   this._tempDirectory = config.tempDirectory || './.nyc_output'
+  this._instrumenterLib = require(config.instrumenter || './lib/instrumenters/istanbul')
   this._reportDir = config.reportDir
+  this._sourceMap = config.sourceMap
   this.cwd = config.cwd
 
   this.reporter = arrify(config.reporter || 'text')
 
-  // load exclude stanza from config.
-  this.include = false
-  if (config.include && config.include.length > 0) {
-    this.include = this._prepGlobPatterns(arrify(config.include))
-  }
-
-  this.exclude = this._prepGlobPatterns(
-    ['**/node_modules/**'].concat(arrify(
-      config.exclude && config.exclude.length > 0
-        ? config.exclude
-        : ['test/**', 'test{,-*}.js', '**/*.test.js', '**/__tests__/**']
-      ))
-  )
-
   this.cacheDirectory = findCacheDir({name: 'nyc', cwd: this.cwd})
 
   this.enableCache = Boolean(this.cacheDirectory && (config.enableCache === true || process.env.NYC_CACHE === 'enable'))
 
+  this.exclude = testExclude({
+    cwd: this.cwd,
+    include: config.include,
+    exclude: config.exclude
+  })
+
   // require extensions can be provided as config in package.json.
   this.require = arrify(config.require)
 
@@ -129,43 +123,7 @@ NYC.prototype.instrumenter = function () {
 }
 
 NYC.prototype._createInstrumenter = function () {
-  var configFile = path.resolve(this.cwd, './.istanbul.yml')
-
-  if (!fs.existsSync(configFile)) configFile = undefined
-
-  var istanbul = this.istanbul()
-
-  var instrumenterConfig = istanbul.config.loadFile(configFile).instrumentation.config
-
-  return new istanbul.Instrumenter({
-    coverageVariable: '__coverage__',
-    embedSource: instrumenterConfig['embed-source'],
-    noCompact: !instrumenterConfig.compact,
-    preserveComments: instrumenterConfig['preserve-comments']
-  })
-}
-
-NYC.prototype._prepGlobPatterns = function (patterns) {
-  if (!patterns) return patterns
-
-  var result = []
-
-  function add (pattern) {
-    if (result.indexOf(pattern) === -1) {
-      result.push(pattern)
-    }
-  }
-
-  patterns.forEach(function (pattern) {
-    // Allow gitignore style of directory exclusion
-    if (!/\/\*\*$/.test(pattern)) {
-      add(pattern.replace(/\/$/, '') + '/**')
-    }
-
-    add(pattern)
-  })
-
-  return result
+  return this._instrumenterLib(this.cwd)
 }
 
 NYC.prototype.addFile = function (filename) {
@@ -190,14 +148,6 @@ NYC.prototype._readTranspiledSource = function (path) {
   return source
 }
 
-NYC.prototype.shouldInstrumentFile = function (filename, relFile) {
-  // Don't instrument files that are outside of the current working directory.
-  if (/^\.\./.test(path.relative(this.cwd, filename))) return false
-
-  relFile = relFile.replace(/^\.[\\\/]/, '') // remove leading './' or '.\'.
-  return (!this.include || micromatch.any(relFile, this.include)) && !micromatch.any(relFile, this.exclude)
-}
-
 NYC.prototype.addAllFiles = function () {
   var _this = this
 
@@ -210,7 +160,7 @@ NYC.prototype.addAllFiles = function () {
     pattern = '**/*{' + this.extensions.join() + '}'
   }
 
-  glob.sync(pattern, {cwd: this.cwd, nodir: true, ignore: this.exclude}).forEach(function (filename) {
+  glob.sync(pattern, {cwd: this.cwd, nodir: true, ignore: this.exclude.exclude}).forEach(function (filename) {
     var obj = _this.addFile(path.join(_this.cwd, filename))
     if (obj.instrument) {
       module._compile(
@@ -224,7 +174,7 @@ NYC.prototype.addAllFiles = function () {
 }
 
 NYC.prototype._maybeInstrumentSource = function (code, filename, relFile) {
-  var instrument = this.shouldInstrumentFile(filename, relFile)
+  var instrument = this.exclude.shouldInstrument(filename, relFile)
 
   if (!instrument) {
     return null
@@ -248,20 +198,24 @@ NYC.prototype._transformFactory = function (cacheDir) {
   return function (code, metadata, hash) {
     var filename = metadata.filename
 
-    var sourceMap = convertSourceMap.fromSource(code) || convertSourceMap.fromMapFileSource(code, path.dirname(filename))
-    if (sourceMap) {
-      if (hash) {
-        var mapPath = path.join(cacheDir, hash + '.map')
-        fs.writeFileSync(mapPath, sourceMap.toJSON())
-      } else {
-        _this.sourceMapCache.addMap(filename, sourceMap.toJSON())
-      }
-    }
+    if (_this._sourceMap) _this._handleSourceMap(cacheDir, code, hash, filename)
 
     return instrumenter.instrumentSync(code, filename)
   }
 }
 
+NYC.prototype._handleSourceMap = function (cacheDir, code, hash, filename) {
+  var sourceMap = convertSourceMap.fromSource(code) || convertSourceMap.fromMapFileSource(code, path.dirname(filename))
+  if (sourceMap) {
+    if (hash) {
+      var mapPath = path.join(cacheDir, hash + '.map')
+      fs.writeFileSync(mapPath, sourceMap.toJSON())
+    } else {
+      this.sourceMapCache.addMap(filename, sourceMap.toJSON())
+    }
+  }
+}
+
 NYC.prototype._handleJs = function (code, filename) {
   var relFile = path.relative(this.cwd, filename)
   return this._maybeInstrumentSource(code, filename, relFile) || code

lib/instrumenters/istanbul.js

@@ -0,0 +1,23 @@
+var fs = require('fs')
+var path = require('path')
+
+function InstrumenterIstanbul (cwd) {
+  var configFile = path.resolve(cwd, './.istanbul.yml')
+
+  if (!fs.existsSync(configFile)) configFile = undefined
+  var istanbul = InstrumenterIstanbul.istanbul()
+  var instrumenterConfig = istanbul.config.loadFile(configFile).instrumentation.config
+
+  return new istanbul.Instrumenter({
+    coverageVariable: '__coverage__',
+    embedSource: instrumenterConfig['embed-source'],
+    noCompact: !instrumenterConfig.compact,
+    preserveComments: instrumenterConfig['preserve-comments']
+  })
+}
+
+InstrumenterIstanbul.istanbul = function () {
+  return InstrumenterIstanbul._istanbul || (InstrumenterIstanbul._istanbul = require('istanbul'))
+}
+
+module.exports = InstrumenterIstanbul

lib/instrumenters/noop.js

@@ -0,0 +1,9 @@
+function NOOP () {
+  return {
+    instrumentSync: function (code) {
+      return code
+    }
+  }
+}
+
+module.exports = NOOP

lib/source-map-cache.js

@@ -165,6 +165,11 @@ SourceMapCache.prototype._rewriteBranches = function (fileReport, sourceMap) {
 
     if (locations.length > 0) {
       b[index + ''] = fileReport.b[k]
+
+      /* istanbul ignore next: hard to test for edge-case,
+         counts for more statements than exist post remapping */
+      while (b[index + ''].length > locations.length) b[index + ''].pop()
+
       branchMap[index + ''] = {
         line: locations[0].start.line,
         type: item.type,

package.json

@@ -22,6 +22,7 @@
     "index.js",
     "bin/*.js",
     "lib/*.js",
+    "lib/instrumenters/*.js",
     "!**/*covered.js"
   ],
   "nyc": {
@@ -85,6 +86,7 @@
     "signal-exit": "^2.1.1",
     "source-map": "^0.5.3",
     "spawn-wrap": "^1.2.2",
+    "test-exclude": "^1.1.0",
     "yargs": "^4.7.0"
   },
   "devDependencies": {
@@ -131,6 +133,7 @@
     "signal-exit",
     "source-map",
     "spawn-wrap",
+    "test-exclude",
     "yargs"
   ]
 }

screen2.png

@@ -0,0 +1 @@
+console.log(JSON.stringify(process.env))