feat: Add support for nyc.config.js

README.md

@@ -320,6 +320,21 @@ Any configuration options that can be set via the command line can also be speci
 }
 ```
 
+Configuration can also be provided by `nyc.config.js` if programmed logic is required:
+```js
+'use strict';
+const {defaultExclude} = require('test-exclude');
+const isWindows = require('is-windows');
+
+let platformExclude = [
+  isWindows() ? 'lib/posix.js' : 'lib/win32.js'
+];
+
+module.exports = {
+  exclude: platformExclude.concat(defaultExclude)
+};
+```
+
 ### Publish, and reuse, your nyc configuration
 
 nyc allows you to inherit other configurations using the key `extends`. As an example,

lib/config-util.js

@@ -19,13 +19,22 @@ function guessCWD (cwd) {
 }
 
 Config.loadConfig = function (argv, cwd) {
-  const rcPath = findUp.sync([argv.nycrcPath || '.nycrc', '.nycrc.json'], { cwd: guessCWD(cwd) })
+  const rcOptions = [
+    argv.nycrcPath || '.nycrc',
+    '.nycrc.json',
+    'nyc.config.js'
+  ]
+  const rcPath = findUp.sync(rcOptions, { cwd: guessCWD(cwd) })
   let config = {}
 
   if (rcPath) {
-    config = JSON.parse(
-      fs.readFileSync(rcPath, 'utf-8')
-    )
+    if (rcPath.toLowerCase().endsWith('.js')) {
+      config = require(rcPath)
+    } else {
+      config = JSON.parse(
+        fs.readFileSync(rcPath, 'utf-8')
+      )
+    }
   }
 
   if (config.require) config.require = arrify(config.require)

test/fixtures/cli/nyc-config-js/ignore.js

@@ -0,0 +1 @@
+var i = 2

test/fixtures/cli/nyc-config-js/index.js

@@ -0,0 +1,11 @@
+require('./ignore')
+
+var a = 0
+
+a++
+
+if (a === 0) {
+  a++;
+  a--;
+  a++;
+}

test/fixtures/cli/nyc-config-js/nyc.config.js

@@ -0,0 +1,3 @@
+module.exports = {
+	exclude: ['nyc.config.js', 'nycrc-config.js', 'ignore.js']
+};

test/fixtures/cli/nyc-config-js/nycrc-config.js

@@ -0,0 +1,9 @@
+module.exports = {
+  'check-coverage': true,
+  'per-file': true,
+  lines: 100,
+  statements: 100,
+  functions: 100,
+  branches: 100,
+  exclude: []
+}

test/fixtures/cli/nyc-config-js/package.json

@@ -0,0 +1,5 @@
+{
+  "nyc": {
+    "reporter": ["text-lcov"]
+  }
+}

test/nyc-integration.js

@@ -367,6 +367,80 @@ describe('the nyc cli', function () {
       })
     })
 
+    describe('nyc.config.js', function () {
+      var cwd = path.resolve(fixturesCLI, './nyc-config-js')
+
+      it('loads configuration from package.json and nyc.config.js', function (done) {
+        var args = [bin, process.execPath, './index.js']
+
+        var proc = spawn(process.execPath, args, {
+          cwd: cwd,
+          env: env
+        })
+
+        var stdout = ''
+        proc.stdout.on('data', function (chunk) {
+          stdout += chunk
+        })
+
+        proc.on('close', function (code) {
+          code.should.equal(0)
+          stdout.should.match(/SF:.*index\.js/)
+          stdout.should.not.match(/SF:.*ignore\.js/)
+          stdout.should.not.match(/SF:.*nyc\.config\.js/)
+          stdout.should.not.match(/SF:.*nycrc-config\.js/)
+          done()
+        })
+      })
+
+      it('loads configuration from different module rather than nyc.config.js', function (done) {
+        var args = [bin, '--all', '--nycrc-path', './nycrc-config.js', process.execPath, './index.js']
+
+        var proc = spawn(process.execPath, args, {
+          cwd: cwd,
+          env: env
+        })
+
+        var stdout = ''
+        proc.stdout.on('data', function (chunk) {
+          stdout += chunk
+        })
+
+        proc.on('close', function (code) {
+          // should be 1 due to coverage check
+          code.should.equal(1)
+          stdout.should.match(/SF:.*index\.js/)
+          stdout.should.match(/SF:.*ignore\.js/)
+          stdout.should.match(/SF:.*nyc\.config\.js/)
+          stdout.should.match(/SF:.*nycrc-config\.js/)
+          done()
+        })
+      })
+
+      it('allows nyc.config.js configuration to be overridden with command line args', function (done) {
+        var args = [bin, '--all', '--exclude=foo.js', process.execPath, './index.js']
+
+        var proc = spawn(process.execPath, args, {
+          cwd: cwd,
+          env: env
+        })
+
+        var stdout = ''
+        proc.stdout.on('data', function (chunk) {
+          stdout += chunk
+        })
+
+        proc.on('close', function (code) {
+          code.should.equal(0)
+          stdout.should.match(/SF:.*index\.js/)
+          stdout.should.match(/SF:.*ignore\.js/)
+          stdout.should.match(/SF:.*nyc\.config\.js/)
+          stdout.should.match(/SF:.*nycrc-config\.js/)
+          done()
+        })
+      })
+    })
+
     describe('.nycrc', function () {
       var cwd = path.resolve(fixturesCLI, './nycrc')