refactor(src): update code base with latest ES2015+ features

Author: michael-ciniawsky

src/Error.js

@@ -1,13 +1,13 @@
-'use strict'
-
 class SyntaxError extends Error {
   constructor (err) {
     super(err)
 
-    this.name = 'Syntax Error'
+    const { line, column, reason } = err
+
+    this.name = 'SyntaxError'
 
     this.message = ''
-    this.message += `${this.name} \n\n(${err.line}:${err.column}) ${err.reason}`
+    this.message += `${this.name} \n\n(${line}:${column}) ${reason}`
     this.message += `\n\n${err.showSourceCode()}\n`
 
     this.stack = false

src/Warning.js

@@ -2,7 +2,7 @@ class Warning extends Error {
   constructor (warning) {
     super()
 
-    const { line, column, text } = warning
+    const { text, line, column } = warning
 
     this.name = 'LoaderWarning'
     this.message = `\n(${line}:${column}) ${text}\n`

src/index.js

@@ -1,10 +1,6 @@
-'use strict'
-
 const path = require('path')
 
-const loaderUtils = require('loader-utils')
-
-const parseOptions = require('./options')
+const { getOptions } = require('loader-utils')
 const validateOptions = require('schema-utils')
 
 const postcss = require('postcss')
@@ -42,7 +38,7 @@ const parseOptions = require('./options.js')
  * @return {cb} cb      Result
  */
 module.exports = function loader (css, map, meta) {
-  const options = Object.assign({}, loaderUtils.getOptions(this))
+  const options = Object.assign({}, getOptions(this))
 
   validateOptions(require('./options.json'), options, 'PostCSS Loader')
 
@@ -96,16 +92,25 @@ module.exports = function loader (css, map, meta) {
 
     return postcssrc(rc.ctx, rc.path)
   }).then((config) => {
-    if (!config) config = {}
+    if (!config) {
+      config = {}
+    }
 
-    if (config.file) this.addDependency(config.file)
+    if (config.file) {
+      this.addDependency(config.file)
+    }
 
     // Disable override `to` option from `postcss.config.js`
-    if (config.options.to) delete config.options.to
+    if (config.options.to) {
+      delete config.options.to
+    }
     // Disable override `from` option from `postcss.config.js`
-    if (config.options.from) delete config.options.from
+    if (config.options.from) {
+      delete config.options.from
+    }
 
     let plugins = config.plugins || []
+
     let options = Object.assign({
       from: file,
       map: sourceMap
@@ -139,29 +144,39 @@ module.exports = function loader (css, map, meta) {
       css = this.exec(css, this.resource)
     }
 
-    if (sourceMap && typeof map === 'string') map = JSON.parse(map)
-    if (sourceMap && map) options.map.prev = map
+    if (sourceMap && typeof map === 'string') {
+      map = JSON.parse(map)
+    }
+
+    if (sourceMap && map) {
+      options.map.prev = map
+    }
 
     return postcss(plugins)
       .process(css, options)
       .then((result) => {
+        let { css, map, root, processor, messages } = result
+
         result.warnings().forEach((warning) => {
           this.emitWarning(new Warning(warning))
         })
 
-        result.messages.forEach((msg) => {
-          if (msg.type === 'dependency') this.addDependency(msg.file)
+        messages.forEach((msg) => {
+          if (msg.type === 'dependency') {
+            this.addDependency(msg.file)
+          }
         })
 
-        css = result.css
-        map = result.map ? result.map.toJSON() : null
+        map = map ? map.toJSON() : null
 
         if (map) {
           map.file = path.resolve(map.file)
           map.sources = map.sources.map((src) => path.resolve(src))
         }
 
-        if (!meta) meta = {}
+        if (!meta) {
+          meta = {}
+        }
 
         const ast = {
           type: 'postcss',
@@ -170,7 +185,7 @@ module.exports = function loader (css, map, meta) {
         }
 
         meta.ast = ast
-        meta.messages = result.messages
+        meta.messages = messages
 
         if (this.loaderIndex === 0) {
           /**
@@ -199,8 +214,12 @@ module.exports = function loader (css, map, meta) {
         return null
       })
   }).catch((err) => {
-    if (err.file) this.addDependency(err.file)
+    if (err.file) {
+      this.addDependency(err.file)
+    }
 
-    return err.name === 'CssSyntaxError' ? cb(new SyntaxError(err)) : cb(err)
+    return err.name === 'CssSyntaxError'
+      ? cb(new SyntaxError(err))
+      : cb(err)
   })
 }

src/options.js

@@ -1,25 +1,21 @@
-'use strict'
-
-module.exports = function parseOptions (params) {
-  if (typeof params.plugins === 'function') {
-    params.plugins = params.plugins.call(this, this)
+function parseOptions ({ exec, parser, syntax, stringifier, plugins }) {
+  if (typeof plugins === 'function') {
+    plugins = plugins.call(this, this)
   }
 
-  let plugins
-
-  if (typeof params.plugins === 'undefined') plugins = []
-  else if (Array.isArray(params.plugins)) plugins = params.plugins
-  else plugins = [ params.plugins ]
+  if (typeof plugins === 'undefined') {
+    plugins = []
+  } else if (!Array.isArray(plugins)) {
+    plugins = [ plugins ]
+  }
 
   const options = {}
 
-  if (typeof params !== 'undefined') {
-    options.parser = params.parser
-    options.syntax = params.syntax
-    options.stringifier = params.stringifier
-  }
-
-  const exec = params && params.exec
+  options.parser = parser
+  options.syntax = syntax
+  options.stringifier = stringifier
 
-  return Promise.resolve({ options: options, plugins: plugins, exec: exec })
+  return Promise.resolve({ options, plugins, exec })
 }
+
+module.exports = parseOptions

test/__snapshots__/Errors.test.js.snap

@@ -1,7 +1,7 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`Errors Syntax Error 1`] = `
-"Syntax Error
+"SyntaxError 
 
 (1:3) Unexpected separator in property