switch to eslint stylistic and flat config

.eslintrc.js

-"use strict";
-module.exports = {
-    env: {
-        es2021: true,
-        node: true,
-    },
-    extends: "eslint:recommended",
-    parserOptions: {
-        sourceType: "script",
-        ecmaVersion: 2022,
-    },
-    rules: {
-        // Annoyances
-        "no-inner-declarations": "off",
-        "no-useless-escape": "warn",
-        "require-atomic-updates": "off",
-        "linebreak-style": "off",
-
-        // Performance/consistency
-        "eqeqeq": [
-            "error",
-            "always",
-            {
-                "null": "ignore",
-            },
-        ],
-        "strict": [
-            "error",
-            "global",
-        ],
-        "no-var": ["error"],
-        "prefer-const": ["warn"],
-        "prefer-template": ["error"],
-
-        // Stylistic
-        "array-element-newline": [
-            "error",
-            "consistent",
-        ],
-        "comma-dangle": ["error", "always-multiline"],
-        "comma-style": ["error", "last"],
-        "indent": [
-            "error",
-            4,
-        ],
-        "quotes": [
-            "error",
-            "double",
-        ],
-        "semi": [
-            "error",
-            "always",
-        ],
-        "no-empty": [
-            "error",
-            {
-                "allowEmptyCatch": true,
-            },
-        ],
-        "no-extra-parens": "error",
-        "brace-style": [ 
-            "error", 
-            "1tbs",
-        ],
-        "object-curly-spacing": [ 
-            "error",
-            "always",
-        ],
-        "eol-last": ["warn", "always"],
-        "key-spacing": ["error"],
-        "keyword-spacing": ["error"],
-        "lines-between-class-members": ["error"],
-        "newline-per-chained-call": ["warn"],
-        "no-unneeded-ternary": ["warn"],
-        "prefer-object-spread": ["warn"],
-        "semi-spacing": ["error"],
-        "space-before-blocks": ["error", "always"],
-        "spaced-comment": ["error", "always"],
-        "arrow-body-style": ["warn", "as-needed"],
-        "arrow-spacing": ["error"],
-    },
-    globals: {
-        "BigInt": true,
-    },
-};

eslint.config.mjs

+import stylistic from "@stylistic/eslint-plugin";
+import js from "@eslint/js";
+import globals from "globals";
+
+export default [
+    js.configs.recommended,
+    stylistic.configs.customize({
+        blockSpacing: true,
+        braceStyle: "1tbs",
+        indent: 4,
+        jsx: true,
+        quotes: "double",
+        semi: true,
+        commaDangle: "always-multiline",
+    }),
+    {
+        files: ["**/*.js"],
+        languageOptions: {
+            sourceType: "commonjs",
+            globals: {
+                ...globals.commonjs,
+            },
+        },
+    },
+    {
+        languageOptions: {
+            globals: {
+                ...globals.browser,
+                ...globals.node,
+            },
+        },
+        rules: {
+            // Annoyances
+            "no-inner-declarations": "off",
+            "require-atomic-updates": "off",
+            "linebreak-style": "off",
+
+            // Performance/consistency
+            "eqeqeq": [
+                "error",
+                "always",
+                {
+                    null: "ignore",
+                },
+            ],
+            "strict": [
+                "error",
+                "global",
+            ],
+            "no-var": ["error"],
+            "prefer-const": ["warn"],
+            "prefer-template": ["error"],
+
+            // Stylistic
+            "@stylistic/array-element-newline": [
+                "error",
+                "consistent",
+            ],
+            "no-empty": [
+                "error",
+                {
+                    allowEmptyCatch: true,
+                },
+            ],
+            "@stylistic/no-extra-parens": "error",
+            "@stylistic/newline-per-chained-call": ["warn"],
+            "no-unneeded-ternary": ["warn"],
+            "prefer-object-spread": ["warn"],
+            "prefer-object-has-own": ["warn"],
+            "arrow-body-style": ["warn", "as-needed"],
+        },
+    },
+];

index.js

-"use strict";
-module.exports = require("./.eslintrc.js");

package.json

 {
   "name": "@tt-bot-dev/eslint-config",
-  "version": "1.1.0",
+  "version": "1.2.0",
   "description": "The ESLint configuration used across all tt-bot-dev repositories.",
-  "main": "index.js",
+  "main": "eslint.config.mjs",
+  "type": "module",
   "scripts": {
     "test": "echo \"Error: no test specified\" && exit 1"
   },
@@ -22,7 +23,12 @@
   },
   "homepage": "https://owo.codes/tt.bot/frameworks/eslint-config",
   "peerDependencies": {
-    "eslint": "^8.5.0"
+    "eslint": "^8.57.0"
   },
-  "private": false
+  "private": false,
+  "dependencies": {
+    "@eslint/js": "^8.57.0",
+    "@stylistic/eslint-plugin": "^1.7.0",
+    "globals": "^14.0.0"
+  }
 }