Integrate `eslint` into the `webpack` build process.

Closes #963

Merge request studip/studip!557

.eslintrc.json

+{
+    "parser": "@babel/eslint-parser",
+    "parserOptions": {
+        "sourceType": "module"
+    },
+    "env": {
+        "browser": true,
+        "es6": true
+    },
+    "extends": "eslint:recommended",
+    "globals": {
+        "STUDIP": "writable",
+        "CKEDITOR": "writable",
+        "$": "writable",
+        "_": "writable",
+        "jQuery": "writable"
+    },
+    "rules": {
+        "no-unused-vars": "off",
+
+        "no-async-promise-executor": "error",
+        "no-await-in-loop": "error",
+        "no-promise-executor-return": "error",
+        "require-atomic-updates": "error",
+        "max-nested-callbacks": ["error", 3],
+        "no-return-await": "error",
+        "prefer-promise-reject-errors": "error"
+    }
+}

package.json

@@ -4,6 +4,7 @@
     "description": "Stud.IP",
     "private": true,
     "scripts": {
+        "lint": "eslint resources/assets/javascripts resources/vue",
         "wds": "webpack serve --progress --config webpack.dev-server.js",
         "webpack-dev": "webpack --config webpack.dev.js --mode development",
         "webpack-prod": "webpack --config webpack.prod.js --mode production",
@@ -19,7 +20,8 @@
         "node": ">=12"
     },
     "devDependencies": {
-        "@babel/core": "^7.12.3",
+        "@babel/core": "^7.17.9",
+        "@babel/eslint-parser": "^7.17.0",
         "@babel/plugin-syntax-dynamic-import": "^7.8.3",
         "@babel/plugin-transform-runtime": "^7.12.1",
         "@babel/preset-env": "^7.12.1",
@@ -45,8 +47,9 @@
         "css-minimizer-webpack-plugin": "^1.1.5",
         "easygettext": "^2.17.0",
         "es6-promise": "4.2.8",
-        "eslint": "7.21.0",
+        "eslint": "^7.32.0",
         "eslint-plugin-vue": "7.7.0",
+        "eslint-webpack-plugin": "^3.1.1",
         "expose-loader": "1.0.1",
         "favico.js": "0.3.10",
         "file-saver": "^2.0.5",
@@ -113,15 +116,6 @@
         "last 2 versions",
         "not IE <= 11"
     ],
-    "eslintConfig": {
-        "env": {
-            "browser": true
-        },
-        "parserOptions": {
-            "ecmaVersion": 6,
-            "sourceType": "module"
-        }
-    },
     "prettier": {
         "printWidth": 120,
         "singleQuote": true,

webpack.common.js

@@ -2,6 +2,7 @@ const webpack = require("webpack");
 const path = require("path");
 const MiniCssExtractPlugin = require("mini-css-extract-plugin");
 const VueLoaderPlugin = require('vue-loader/lib/plugin');
+const ESLintPlugin = require('eslint-webpack-plugin');
 
 const assetsPath = path.resolve(__dirname, "resources/assets/javascripts");
 
@@ -106,6 +107,14 @@ module.exports = {
             filename: "stylesheets/[name].css",
             chunkFilename: "stylesheets/[name].css?h=[chunkhash]"
         }),
+        new ESLintPlugin({
+            exclude: [
+                'node_modules',
+                'public/assets/javascripts/ckeditor/ckeditor.js',
+                'resources/assets/javascripts/vendor',
+                'resources/assets/javascripts/jquery/jstree/jquery.jstree.js',
+            ]
+        }),
     ],
     resolve: {
         alias: {