feat: Add support for yaml configuration file

lib/config-util.js

@@ -40,13 +40,23 @@ Config.loadConfig = function (argv, cwd) {
     if (rcPathLower.endsWith('.js')) {
       config = require(rcPath)
     } else if (/.+\.y(a?)ml$/.test(rcPathLower)) {
-      if (moduleExists('js-yaml')) {
-        console.error('you need to install js-yaml to use a yaml configuration file')
-        process.exit(1)
+      const installedYamlParser = ['js-yaml', 'yaml'].find((name) => moduleExists(name))
+      switch (installedYamlParser) {
+        case 'js-yaml':
+          config = require('js-yaml').load(
+            fs.readFileSync(rcPath, 'utf8')
+          )
+          break
+        case 'yaml':
+          config = require('yaml').parse(
+            fs.readFileSync(rcPath, 'utf8')
+          )
+          break
+        /* istanbul ignore next */
+        default:
+          console.error('you need to install a yaml parser to use a yaml configuration file')
+          process.exit(1)
       }
-      config = require('js-yaml').load(
-        fs.readFileSync(rcPath, 'utf8')
-      )
     } else {
       config = JSON.parse(
         fs.readFileSync(rcPath, 'utf-8')

package.json

@@ -97,6 +97,7 @@
     "coveralls": "^3.0.3",
     "glob": "^7.1.3",
     "is-windows": "^1.0.2",
+    "js-yaml": "^3.13.0",
     "lodash": "^4.17.11",
     "newline-regex": "^0.2.1",
     "requirejs": "^2.3.6",
@@ -107,6 +108,7 @@
     "strip-indent": "^2.0.0",
     "tap": "^12.6.1",
     "which": "^1.3.1",
+    "yaml": "^1.4.0",
     "zero-fill": "^2.2.3"
   },
   "engines": {

test/fixtures/cli/nycrc/.nycrc.yaml

@@ -0,0 +1,2 @@
+exclude:
+- ignore.js

test/fixtures/cli/nycrc/.nycrc.yml

@@ -0,0 +1,2 @@
+exclude:
+- ignore.js

test/nyc-integration.js

@@ -488,6 +488,48 @@ describe('the nyc cli', function () {
         })
       })
 
+      it('loads configuration from .nycrc.yml', function (done) {
+        var args = [bin, '--nycrc-path', './.nycrc.yml', 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/)
+          done()
+        })
+      })
+
+      it('loads configuration from .nycrc.yaml', function (done) {
+        var args = [bin, '--nycrc-path', './.nycrc.yaml', 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/)
+          done()
+        })
+      })
+
       it('allows .nycrc configuration to be overridden with command line args', function (done) {
         var args = [bin, '--exclude=foo.js', process.execPath, './index.js']