finally bump eslint to 9.x

eslint.config.mjs

@@ -0,0 +1,70 @@
+import { FlatCompat } from "@eslint/eslintrc";
+import js from "@eslint/js";
+import typescriptEslint from "typescript-eslint";
+import prettierRecommended from "eslint-plugin-prettier/recommended";
+import customConfig from "@jakejarvis/eslint-config";
+import * as mdx from "eslint-plugin-mdx";
+
+const compat = new FlatCompat({
+  baseDirectory: import.meta.dirname,
+});
+
+// eslint-disable-next-line import/no-anonymous-default-export
+export default [
+  { ignores: ["README.md", ".next", ".vercel", "node_modules"] },
+  js.configs.recommended,
+  ...typescriptEslint.configs.recommended,
+  ...compat.extends("next/core-web-vitals"),
+  prettierRecommended,
+  ...customConfig,
+  {
+    rules: {
+      "prettier/prettier": [
+        "error",
+        {},
+        {
+          usePrettierrc: true,
+        },
+      ],
+    },
+  },
+  {
+    files: ["**/*.ts", "**/*.tsx", "**/*.js", "**/*.jsx"],
+    rules: {
+      camelcase: "off",
+      "@typescript-eslint/ban-ts-comment": "off",
+      "@typescript-eslint/no-explicit-any": "warn",
+      "react/no-unescaped-entities": "off",
+      "react/jsx-boolean-value": "error",
+
+      "react/jsx-wrap-multilines": [
+        "error",
+        {
+          arrow: "parens-new-line",
+          assignment: "parens-new-line",
+          condition: "parens-new-line",
+          declaration: "parens-new-line",
+          logical: "parens-new-line",
+          prop: "ignore",
+          return: "parens-new-line",
+        },
+      ],
+    },
+  },
+  {
+    ...mdx.flat,
+    processor: mdx.createRemarkProcessor({
+      lintCodeBlocks: false,
+    }),
+    rules: {
+      "mdx/remark": "warn",
+      "mdx/code-blocks": "off",
+      "react/jsx-no-undef": "off",
+      "react/jsx-boolean-value": "off",
+      "react/no-unescaped-entities": "off",
+      // TODO: skip these correctly
+      "max-len": "off",
+      semi: "off",
+    },
+  },
+];