build(frontend): account for moved eslint config file with new syntax

.eslintrc.json

@@ -1,30 +0,0 @@
-{
-    "env": {
-        "browser": true,
-        "es6": true,
-        "jasmine": true
-    },
-    "extends": "eslint:recommended",
-    "globals": {
-        "Atomics": "readonly",
-        "SharedArrayBuffer": "readonly",
-        "flatpickr": "readonly",
-        "$": "readonly"
-    },
-    "parser": "@babel/eslint-parser",
-    "parserOptions": {
-        "ecmaVersion": 2018,
-        "requireConfigFile": false,
-        "ecmaFeatures": {
-            "legacyDecorators": true
-        }
-    },
-    "rules": {
-        "no-console": "off",
-        "no-extra-semi": "off",
-        "semi": ["error", "always"],
-        "comma-dangle": ["error", "always-multiline"],
-        "quotes": ["error", "single"],
-        "no-var": "error"
-    }
-}

Makefile

@@ -107,7 +107,7 @@ frontend-%: node_modules well-known --frontend-%;
 --frontend-watch: --frontend-build
 
 .PHONY: --frontend-lint
---frontend-lint: .eslintrc.json
+--frontend-lint: eslint.config.js
 	npx -- eslint frontend/src $(FIX)
 	@echo Hooray! There are no hints.
 

eslint.config.js

@@ -0,0 +1,33 @@
+import js from "@eslint/js";
+import globals from "globals";
+import babelParser from "@babel/eslint-parser";
+
+export default [
+    js.configs.recommended,
+    {
+        files: ["**/*.js"],
+        plugins: {},
+        languageOptions: {
+            ecmaVersion: 2018,
+            globals: {
+                ...globals.browser,
+                ...globals.es6,
+                ...globals.node,
+                ...globals.jasmine,
+                Atomics: "readonly",
+                SharedArrayBuffer: "readonly",
+                flatpickr: "readonly",
+                $: "readonly",
+            },
+            parser: babelParser,
+        },
+        rules: {
+            "no-console": "off",
+            "no-extra-semi": "off",
+            "semi": ["error", "always"],
+            "comma-dangle": ["error", "always-multiline"],
+            "quotes": ["error", "single"],
+            "no-var": "error",
+        },
+    },
+];