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

Author: ghusse

.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;
     }
   }