Load options and plugins from postcss-load-config

Author: Andrey Kuzmin

index.js

@@ -3,13 +3,10 @@ var postcss = require('postcss')
 var applySourceMap = require('vinyl-sourcemaps-apply')
 var gutil = require('gulp-util')
 var path = require('path')
+var postcssLoadConfig = require('postcss-load-config')
 
 
-module.exports = function (processors, options) {
-
-  if (!Array.isArray(processors)) {
-    throw new gutil.PluginError('gulp-postcss', 'Please provide array of postcss processors!')
-  }
+module.exports = withConfigLoader(function (loadConfig) {
 
   var stream = new Stream.Transform({ objectMode: true })
 
@@ -23,29 +20,40 @@ module.exports = function (processors, options) {
       return handleError('Streams are not supported!')
     }
 
-    // Source map is disabled by default
-    var opts = { map: false }
-    var attr
-
-    // Extend default options
-    if (options) {
-      for (attr in options) {
-        if (options.hasOwnProperty(attr)) {
-          opts[attr] = options[attr]
-        }
-      }
-    }
-
-    opts.from = file.path
-    opts.to = opts.to || file.path
+    // Protect `from` and `map` if using gulp-sourcemap
+    var isProtected = file.sourceMap
+      ? { from: true, map: true }
+      : {}
 
-    // Generate separate source map for gulp-sourcemap
-    if (file.sourceMap) {
-      opts.map = { annotation: false }
+    var options = {
+      from: file.path
+    , to: file.path
+      // Generate a separate source map for gulp-sourcemap
+    , map: file.sourceMap ? { annotation: false } : false
     }
 
-    postcss(processors)
-      .process(file.contents, opts)
+    loadConfig({
+      from: options.from
+    , to: options.to
+    , map: options.map
+    })
+      .then(function (config) {
+        var configOpts = config.options || {}
+        // Extend the default options if not protected
+        for (var opt in configOpts) {
+          if (configOpts.hasOwnProperty(opt) && !isProtected[opt]) {
+            options[opt] = configOpts[opt]
+          } else {
+            gutil.log(
+              'gulp-postcss:',
+              file.relative + '\nCannot override ' + opt +
+              ' option, because it is required by gulp-sourcemap'
+            )
+          }
+        }
+        return postcss(config.plugins || [])
+          .process(file.contents, options)
+      })
       .then(handleResult, handleError)
 
     function handleResult (result) {
@@ -89,4 +97,25 @@ module.exports = function (processors, options) {
   }
 
   return stream
+})
+
+
+function withConfigLoader(cb) {
+  return function (plugins, options) {
+    if (typeof plugins === 'undefined') {
+      return cb(postcssLoadConfig)
+    } else if (Array.isArray(plugins)) {
+      return cb(function () {
+        return Promise.resolve({
+          plugins: plugins
+        , options: options
+        })
+      })
+    } else {
+      throw new gutil.PluginError(
+        'gulp-postcss',
+        'Please provide array of postcss processors!'
+      )
+    }
+  }
 }

package.json

@@ -23,14 +23,15 @@
   },
   "homepage": "https://github.com/postcss/gulp-postcss",
   "dependencies": {
-    "gulp-util": "^3.0.7",
-    "postcss": "^5.2.0",
-    "vinyl-sourcemaps-apply": "^0.2.0"
+    "gulp-util": "^3.0.8",
+    "postcss": "^5.2.10",
+    "postcss-load-config": "^1.1.0",
+    "vinyl-sourcemaps-apply": "^0.2.1"
   },
   "devDependencies": {
-    "es6-promise": "^3.0.2",
-    "gulp-sourcemaps": "^1.5.1",
-    "mocha": "^2.2.5",
+    "es6-promise": "^3.3.1",
+    "gulp-sourcemaps": "^1.11.0",
+    "mocha": "^3.2.0",
     "proxyquire": "^1.7.4",
     "sinon": "^1.17.3"
   }

test.js

@@ -93,11 +93,9 @@ it('should respond with error on stream files', function (cb) {
 })
 
 
-it('should throw error if processors are not provided', function (cb) {
-  assert.throws( function () { postcss() }, gutil.PluginError )
+it('should throw error if plugins are not array', function () {
   assert.throws( function () { postcss('') }, gutil.PluginError )
   assert.throws( function () { postcss({}) }, gutil.PluginError )
-  cb()
 })
 
 
@@ -171,13 +169,22 @@ describe('PostCSS Guidelines', function () {
     use: function () {}
   , process: function () {}
   }
+  var postcssLoadConfigStub
   var postcss = proxyquire('./index', {
-    postcss: function () {
+    postcss: function (plugins) {
+      postcssStub.use(plugins)
       return postcssStub
     }
+  , 'postcss-load-config': function (args) {
+      return postcssLoadConfigStub(args)
+    }
+  , 'vinyl-sourcemaps-apply': function () {
+      return {}
+    }
   })
 
   beforeEach(function () {
+    postcssLoadConfigStub = sandbox.stub()
     sandbox.stub(postcssStub, 'use')
     sandbox.stub(postcssStub, 'process')
   })
@@ -186,7 +193,6 @@ describe('PostCSS Guidelines', function () {
     sandbox.restore()
   })
 
-
   it('should set `from` and `to` processing options to `file.path`', function (cb) {
 
     var stream = postcss([ doubler ])
@@ -236,6 +242,82 @@ describe('PostCSS Guidelines', function () {
 
   })
 
+  it('should take plugins and options from postcss-load-config', function (cb) {
+
+    var cssPath = __dirname + '/fixture.css'
+    var stream = postcss()
+    var plugins = [ doubler ]
+
+    postcssLoadConfigStub.returns(Promise.resolve({
+      plugins: plugins
+    , options: { to: 'overriden' }
+    }))
+
+    postcssStub.process.returns(Promise.resolve({
+      css: ''
+    , warnings: function () {
+        return []
+      }
+    }))
+
+    stream.on('data', function () {
+      assert.deepEqual(postcssLoadConfigStub.getCall(0).args[0], {
+        from: cssPath
+      , to: cssPath
+      , map: false
+      })
+      assert.equal(postcssStub.use.getCall(0).args[0], plugins)
+      assert.equal(postcssStub.process.getCall(0).args[1].to, 'overriden')
+      cb()
+    })
+
+    stream.write(new gutil.File({
+      contents: new Buffer('a {}')
+    , path: cssPath
+    }))
+
+    stream.end()
+
+  })
+
+  it('should not override `from` and `map` if using source maps', function (cb) {
+    var stream = postcss([ doubler ], { from: 'overriden', map: 'overriden' })
+    var cssPath = __dirname + '/fixture.css'
+    postcssStub.process.returns(Promise.resolve({
+      css: ''
+    , warnings: function () {
+        return []
+      }
+    , map: {
+        toJSON: function () {
+          return {
+            sources: [],
+            file: ''
+          }
+        }
+      }
+    }))
+
+    sandbox.stub(gutil, 'log')
+
+    stream.on('data', function () {
+      assert.deepEqual(postcssStub.process.getCall(0).args[1].from, cssPath)
+      assert.deepEqual(postcssStub.process.getCall(0).args[1].map, { annotation: false })
+      var firstMessage = gutil.log.getCall(0).args[1]
+      var secondMessage = gutil.log.getCall(1).args[1]
+      assert(firstMessage, '/fixture.css\nCannot override from option, because it is required by gulp-sourcemap')
+      assert(secondMessage, '/fixture.css\nCannot override map option, because it is required by gulp-sourcemap')
+      cb()
+    })
+
+    var file = new gutil.File({
+      contents: new Buffer('a {}')
+    , path: cssPath
+    })
+    file.sourceMap = {}
+    stream.end(file)
+  })
+
   it('should not output js stack trace for `CssSyntaxError`', function (cb) {
 
     var stream = postcss([ doubler ])