Add eslint, modernize code

Author: WebFreak001

eslint.config.mts

@@ -0,0 +1,20 @@
+import js from "@eslint/js";
+import globals from "globals";
+import tseslint from "typescript-eslint";
+import { defineConfig } from "eslint/config";
+
+export default defineConfig([
+	{
+		files: ["**/*.{js,mjs,cjs,ts,mts,cts}"],
+		plugins: { js },
+		extends: ["js/recommended"],
+		languageOptions: { globals: globals.node },
+		rules: {
+			"@typescript-eslint/no-unused-vars": [
+				"error",
+				{ varsIgnorePattern: "^_", argsIgnorePattern: "^_" },
+			],
+		},
+	},
+	tseslint.configs.recommended,
+]);