Uses ESLint to catch errors and fixes ESLint errors #173 (#180)

* Uses ESLint to catch errors and fixes ESLint errors #173

* Changes ESLint configuration to allows usage of console

* Launches npm run lint before git commit

* Adds missing ESLint config files

* Runs ESLint in AppVeyor

* Fixes a regression introduced previously, fixes new warnings

* Fixes new ESLint errors introduced in master

* Specifies ecmaVersion=5 in builtins and fixes errors in index.js

.eslintignore

@@ -0,0 +1,20 @@
+# ESLint does not support both
+#   - import used as a function, and
+#   - the export statement
+# in the same file
+
+/test/integration/dynamic/index.js
+/test/integration/dynamic-css/index.js
+/test/integration/dynamic-esm/index.js
+/test/integration/dynamic-hoist/index.js
+/test/integration/dynamic-references-raw/index.js
+/test/integration/dynamic-references-raw/local.js
+/test/integration/hmr-dynamic/index.js
+
+# Generated by the build
+lib
+dist
+/test/dist
+/test/input
+
+coverage

.eslintrc.json

@@ -0,0 +1,10 @@
+{
+  "extends": "eslint:recommended",
+  "parserOptions": {
+    "ecmaVersion": 8    
+  },
+  "env": {
+    "node": true,
+    "es6": true
+  }
+}

.travis.yml

@@ -4,5 +4,7 @@ node_js:
   # - '6'
   - '8'
 cache: yarn
-script: yarn test
+script: 
+  - yarn test
+  - yarn lint
 sudo: false

appveyor.yml

@@ -16,6 +16,8 @@ test_script:
   - yarn --version
   # run tests
   - yarn test
+  # run ESlint
+  - yarn lint
 
 cache:
  - "%LOCALAPPDATA%\\Yarn"

bin/.eslintrc.json

@@ -0,0 +1,6 @@
+{
+  "extends": "../.eslintrc.json",
+  "rules": {
+    "no-console": 0
+  }
+}

package.json

@@ -45,6 +45,7 @@
     "babel-preset-env": "^1.6.1",
     "coffeescript": "^2.0.3",
     "cross-env": "^5.1.1",
+    "eslint": "^4.13.0",
     "husky": "^0.14.3",
     "less": "^2.7.2",
     "lint-staged": "^6.0.0",
@@ -65,7 +66,8 @@
     "format": "prettier --write './{src,bin,test}/**/*.{js,json,md}'",
     "build": "babel src -d lib",
     "prepublish": "yarn build",
-    "precommit": "lint-staged",
+    "precommit": "npm run lint && lint-staged",
+    "lint": "eslint .",
     "postinstall":
       "node -e \"console.log('\\u001b[35m\\u001b[1mLove Parcel? You can now donate to our open collective:\\u001b[22m\\u001b[39m\\n > \\u001b[34mhttps://opencollective.com/parcel/donate\\u001b[0m')\""
   },

src/.eslintrc.json

@@ -0,0 +1,6 @@
+{
+  "extends": "../.eslintrc.json",
+  "rules": {
+    "no-console": 0
+  }
+}

src/Asset.js

@@ -71,10 +71,7 @@ class Asset {
       from = this.name;
     }
 
-    let resolved = path
-      .resolve(path.dirname(from), url)
-      .replace(/[\?#].*$/, '');
-
+    let resolved = path.resolve(path.dirname(from), url).replace(/[?#].*$/, '');
     this.addDependency(
       './' + path.relative(path.dirname(this.name), resolved),
       Object.assign({dynamic: true}, opts)

src/Bundle.js

@@ -1,5 +1,4 @@
 const Path = require('path');
-const fs = require('fs');
 const crypto = require('crypto');
 
 /**

src/Bundler.js

@@ -2,7 +2,6 @@ const fs = require('./utils/fs');
 const Resolver = require('./Resolver');
 const Parser = require('./Parser');
 const WorkerFarm = require('./WorkerFarm');
-const worker = require('./utils/promisify')(require('./worker.js'));
 const Path = require('path');
 const Bundle = require('./Bundle');
 const {FSWatcher} = require('chokidar');
@@ -13,7 +12,6 @@ const {EventEmitter} = require('events');
 const Logger = require('./Logger');
 const PackagerRegistry = require('./packagers');
 const localRequire = require('./utils/localRequire');
-const customErrors = require('./utils/customErrors');
 const config = require('./utils/config');
 
 /**
@@ -273,8 +271,10 @@ class Bundler extends EventEmitter {
     try {
       return await this.resolveAsset(dep.name, asset.name);
     } catch (err) {
-      if (err.message.indexOf(`Cannot find module '${dep.name}'`) === 0) {
-        err.message = `Cannot resolve dependency '${dep.name}'`;
+      let thrown = err;
+
+      if (thrown.message.indexOf(`Cannot find module '${dep.name}'`) === 0) {
+        thrown.message = `Cannot resolve dependency '${dep.name}'`;
 
         // Add absolute path to the error message if the dependency specifies a relative path
         if (dep.name.startsWith('.')) {
@@ -285,13 +285,13 @@ class Bundler extends EventEmitter {
         // Generate a code frame where the dependency was used
         if (dep.loc) {
           await asset.loadIfNeeded();
-          err.loc = dep.loc;
-          err = asset.generateErrorMessage(err);
+          thrown.loc = dep.loc;
+          thrown = asset.generateErrorMessage(thrown);
         }
 
-        err.fileName = asset.name;
+        thrown.fileName = asset.name;
       }
-      throw err;
+      throw thrown;
     }
   }
 

src/FSCache.js

@@ -70,7 +70,9 @@ class FSCache {
     try {
       await fs.unlink(this.getCacheFile(filename));
       this.invalidated.delete(filename);
-    } catch (err) {}
+    } catch (err) {
+      // Fail silently
+    }
   }
 }
 

src/Server.js

@@ -1,6 +1,4 @@
 const http = require('http');
-const path = require('path');
-const url = require('url');
 const serveStatic = require('serve-static');
 const getPort = require('get-port');
 const serverErrors = require('./utils/customErrors').serverErrors;
@@ -66,7 +64,7 @@ async function serve(bundler, port) {
       reject(err);
     });
 
-    server.once('listening', connection => {
+    server.once('listening', () => {
       let addon =
         server.address().port !== port
           ? `- ${bundler.logger.chalk.red(

src/assets/CSSAsset.js

@@ -1,12 +1,10 @@
 const Asset = require('../Asset');
 const postcss = require('postcss');
 const valueParser = require('postcss-value-parser');
-const path = require('path');
-const md5 = require('../utils/md5');
 const postcssTransform = require('../transforms/postcss');
 const CssSyntaxError = require('postcss/lib/css-syntax-error');
 
-const URL_RE = /url\s*\(\"?(?![a-z]+:)/;
+const URL_RE = /url\s*\("?(?![a-z]+:)/;
 const IMPORT_RE = /@import/;
 const PROTOCOL_RE = /^[a-z]+:/;
 

src/assets/CoffeeScriptAsset.js

@@ -1,5 +1,4 @@
 const JSAsset = require('./JSAsset');
-const config = require('../utils/config');
 const localRequire = require('../utils/localRequire');
 
 class CoffeeScriptAsset extends JSAsset {

src/assets/GlobAsset.js

@@ -1,7 +1,5 @@
 const Asset = require('../Asset');
 const glob = require('glob');
-const promisify = require('../utils/promisify');
-const globPromise = promisify(glob);
 const micromatch = require('micromatch');
 const path = require('path');
 
@@ -29,7 +27,8 @@ class GlobAsset extends Asset {
         .slice(1)
         .filter(Boolean)
         .reduce((a, p) => a.concat(p.split('/')), []);
-      let relative = './' + path.relative(path.dirname(this.name), file.normalize('NFC'));
+      let relative =
+        './' + path.relative(path.dirname(this.name), file.normalize('NFC'));
       set(matches, parts, relative);
       this.addDependency(relative);
     }

src/assets/HTMLAsset.js

@@ -1,10 +1,8 @@
 const Asset = require('../Asset');
-const posthtml = require('posthtml');
 const parse = require('posthtml-parser');
 const api = require('posthtml/lib/api');
 const path = require('path');
 const url = require('url');
-const md5 = require('../utils/md5');
 const render = require('posthtml-render');
 const posthtmlTransform = require('../transforms/posthtml');
 const isURL = require('../utils/is-url');

src/assets/LESSAsset.js

@@ -32,7 +32,7 @@ function urlPlugin(asset) {
   return {
     install: (less, pluginManager) => {
       let visitor = new less.visitors.Visitor({
-        visitUrl: (node, args) => {
+        visitUrl: (node) => {
           node.value.value = asset.addURLDependency(
             node.value.value,
             node.currentFileInfo.filename

src/builtins/.eslintrc.json

@@ -0,0 +1,12 @@
+{
+  "extends": "../.eslintrc.json",
+  "parserOptions": {
+    "ecmaVersion": 5
+  },
+  "env": {
+    "browser": true
+  },
+  "rules": {
+    "no-global-assign": 1
+  }
+}

src/builtins/bundle-url.js

@@ -12,7 +12,7 @@ function getBundleURL() {
   try {
     throw new Error;
   } catch (err) {
-    var matches = ('' + err.stack).match(/(https?|file|ftp):\/\/[^\)\n]+/g);
+    var matches = ('' + err.stack).match(/(https?|file|ftp):\/\/[^)\n]+/g);
     if (matches) {
       return getBaseURL(matches[0]);
     }
@@ -22,7 +22,7 @@ function getBundleURL() {
 }
 
 function getBaseURL(url) {
-  return ('' + url).replace(/^((?:https?|file|ftp):\/\/.+)\/[^\/]+$/, '$1') + '/';
+  return ('' + url).replace(/^((?:https?|file|ftp):\/\/.+)\/[^/]+$/, '$1') + '/';
 }
 
 exports.getBundleURL = getBundleURLCached;

src/builtins/css-loader.js

@@ -25,6 +25,6 @@ function reloadCSS() {
 
     cssTimeout = null;
   }, 50);
-};
+}
 
 module.exports = reloadCSS;

src/builtins/index.js

@@ -1,6 +1,6 @@
-const builtins = require('node-libs-browser');
+var builtins = require('node-libs-browser');
 
-for (let key in builtins) {
+for (var key in builtins) {
   if (builtins[key] == null) {
     builtins[key] = require.resolve('./_empty.js');
   }

src/builtins/prelude.js

@@ -33,20 +33,23 @@ require = (function (modules, cache, entry) {
         err.code = 'MODULE_NOT_FOUND';
         throw err;
       }
-
-      function localRequire(x) {
-        return newRequire(localRequire.resolve(x));
-      }
-
-      localRequire.resolve = function (x) {
-        return modules[name][1][x] || x;
-      };
+
+      localRequire.resolve = resolve;
 
       var module = cache[name] = new newRequire.Module;
+
       modules[name][0].call(module.exports, localRequire, module, module.exports);
     }
 
     return cache[name].exports;
+
+    function localRequire(x){
+      return newRequire(localRequire.resolve(x));
+    }
+
+    function resolve(x){
+      return modules[name][1][x] || x;
+    }
   }
 
   function Module() {

src/packagers/Packager.js

@@ -17,6 +17,7 @@ class Packager {
 
   async start() {}
 
+  // eslint-disable-next-line no-unused-vars
   async addAsset(asset) {
     throw new Error('Must be implemented by subclasses');
   }

src/transforms/babel.js

@@ -1,5 +1,4 @@
 const babel = require('babel-core');
-const path = require('path');
 const config = require('../utils/config');
 
 module.exports = async function(asset) {

src/utils/is-url.js

@@ -4,7 +4,7 @@ const isURL = require('is-url');
 const ANCHOR_REGEXP = /^#/;
 
 // Matches scheme (ie: tel:, mailto:, data:)
-const SCHEME_REGEXP = /^[a-z]*\:/i;
+const SCHEME_REGEXP = /^[a-z]*:/i;
 
 module.exports = function(url) {
   return isURL(url) || ANCHOR_REGEXP.test(url) || SCHEME_REGEXP.test(url);

src/visitors/dependencies.js

@@ -1,5 +1,4 @@
 const types = require('babel-types');
-const {resolve} = require('path');
 const template = require('babel-template');
 
 const requireTemplate = template('require("_bundle_loader")');

src/visitors/fs.js

@@ -20,7 +20,6 @@ module.exports = {
   },
 
   CallExpression(path, asset) {
-    let callee = path.node.callee;
     if (referencesImport(path, 'fs', 'readFileSync')) {
       let vars = {
         __dirname: Path.dirname(asset.name),

src/visitors/globals.js

@@ -1,4 +1,3 @@
-const template = require('babel-template');
 const Path = require('path');
 const types = require('babel-types');
 
@@ -18,7 +17,7 @@ const VARS = {
 };
 
 module.exports = {
-  MemberExpression(node, asset, ancestors) {
+  MemberExpression(node, asset) {
     // Inline environment variables accessed on process.env
     if (matchesPattern(node.object, 'process.env')) {
       let key = types.toComputedKey(node);

src/worker.js

@@ -1,14 +1,8 @@
 require('v8-compile-cache');
-const fs = require('./utils/fs');
 const Parser = require('./Parser');
-const babel = require('./transforms/babel');
 
 let parser;
 
-function emit(event, ...args) {
-  process.send({event, args});
-}
-
 exports.init = function(options, callback) {
   parser = new Parser(options || {});
   callback();
@@ -25,11 +19,13 @@ exports.run = async function(path, pkg, options, callback) {
       hash: asset.hash
     });
   } catch (err) {
+    let returned = err;
+
     if (asset) {
-      err = asset.generateErrorMessage(err);
+      returned = asset.generateErrorMessage(returned);
     }
 
-    err.fileName = path;
-    callback(err);
+    returned.fileName = path;
+    callback(returned);
   }
 };