diff --git a/packages/eslint-config/src/globs.ts b/packages/eslint-config/src/globs.ts
index a265183..13303d5 100644
--- a/packages/eslint-config/src/globs.ts
+++ b/packages/eslint-config/src/globs.ts
@@ -44,5 +44,5 @@ export function globAsFormat(glob: string) {
  * Apply custom rules to snippets in markdown files.
  */
 export function globMarkdownSnippetFromGlob(glob: string) {
-	return `**/*.md/*.${glob.split("/").pop()}`;
+	return `**/*.md/*.${glob.split("/").pop() ?? ""}`;
 }
diff --git a/packages/eslint-config/src/index.ts b/packages/eslint-config/src/index.ts
index a07ede3..a3f099b 100644
--- a/packages/eslint-config/src/index.ts
+++ b/packages/eslint-config/src/index.ts
@@ -1,8 +1,9 @@
 import { FlatConfig } from "@typescript-eslint/utils/ts-eslint";
 import { globUse } from "./globs.js";
+import { javascript } from "./javascript.js";
 import { markdownConfig } from "./markdown.js";
 import { prettierConfig, PrettierConfig } from "./prettier.js";
-import { typescript, TypescriptConfig } from "./typescript.js";
+import { typescript, TypescriptConfig, typescriptResolveConfig } from "./typescript.js";
 
 interface Opts {
 	prettier?: PrettierConfig;
@@ -23,6 +24,8 @@ export function defineConfig(opts: Opts, ...userConfigs: FlatConfig.Config[]) {
 		}
 	}
 
+	opts.typescript = typescriptResolveConfig(opts.typescript);
+
 	return [
 		// Global options
 		{
@@ -38,6 +41,7 @@ export function defineConfig(opts: Opts, ...userConfigs: FlatConfig.Config[]) {
 
 		// Language specifics
 		...markdownConfig(),
+		...javascript(!!opts.typescript),
 		...typescript(opts.typescript),
 
 		// Ecosystem specific
diff --git a/packages/eslint-config/src/javascript.ts b/packages/eslint-config/src/javascript.ts
new file mode 100644
index 0000000..179fb1c
--- /dev/null
+++ b/packages/eslint-config/src/javascript.ts
@@ -0,0 +1,18 @@
+import { FlatConfig } from "@typescript-eslint/utils/ts-eslint";
+import eslintConfigs from "@eslint/js";
+import { GLOBS, globUse } from "./globs.js";
+
+export function javascript(hasTypescriptEnabled: boolean) {
+	if (hasTypescriptEnabled) {
+		return [];
+	}
+
+	return [
+		{
+			files: globUse([GLOBS.javascript]),
+			rules: {
+				...eslintConfigs.configs.recommended.rules,
+			},
+		},
+	] satisfies FlatConfig.Config[];
+}
diff --git a/packages/eslint-config/src/typescript.ts b/packages/eslint-config/src/typescript.ts
index c978139..5f0f380 100644
--- a/packages/eslint-config/src/typescript.ts
+++ b/packages/eslint-config/src/typescript.ts
@@ -6,25 +6,47 @@ import { GLOBS, globUse } from "./globs.js";
 export type TypescriptConfig =
 	| boolean
 	| {
-			project?: string;
+			project?: boolean | string;
 	  };
 
-export function typescript(config?: TypescriptConfig) {
+export function typescriptResolveConfig(config?: TypescriptConfig): TypescriptConfig {
+	if (config === false) {
+		return false;
+	}
+
+	if (config === true) {
+		config = {
+			project: true,
+		};
+	}
+
 	if (config === undefined) {
 		if (existsSync("./tsconfig.eslint.json")) {
 			config = {
 				project: "./tsconfig.eslint.json",
 			};
+		} else if (existsSync("./tsconfig.json")) {
+			config = {
+				project: "./tsconfig.json",
+			};
 		} else {
-			config = existsSync("./tsconfig.json");
+			config = false;
 		}
 	}
 
+	return config;
+}
+
+export function typescript(config: TypescriptConfig) {
 	if (config === false) {
 		return [];
 	}
 
-	const project = typeof config === "boolean" ? config : config.project;
+	if (typeof config === "boolean") {
+		config = {
+			project: true,
+		};
+	}
 
 	return [
 		{
@@ -35,7 +57,7 @@ export function typescript(config?: TypescriptConfig) {
 			languageOptions: {
 				parser: typescriptEslint.parser,
 				parserOptions: {
-					project,
+					project: config.project,
 					warnOnUnsupportedTypeScriptVersion: false,
 				},
 			},
diff --git a/packages/eslint-config/test/index.ts b/packages/eslint-config/test/index.ts
index 20d38a7..8ac1d56 100644
--- a/packages/eslint-config/test/index.ts
+++ b/packages/eslint-config/test/index.ts
@@ -232,5 +232,17 @@ const foo = 'bar';
 			);
 			assert.match(stdoutLinesForFile(stdout, "index.ts"), /\(format\/prettier\)/);
 		});
+
+		void it("enables js file linting without tsconfig.json", async () => {
+			const { stdout } = await testOnStdout({}, [
+				{
+					path: "index.js",
+					contents: `let foo= 2`,
+				},
+			]);
+
+			assert.match(stdoutLinesForFile(stdout, "index.js"), /\(no-unused-vars\)/);
+			assert.match(stdoutLinesForFile(stdout, "index.js"), /\(format\/prettier\)/);
+		});
 	},
 );