fix: remove interopDefault to use jiti's default (#19697)

sethamus · web-flow · commit fd467bb892d7 · 2025-05-28T10:50:06.000-04:00
* fix: remove interopDefault to use jiti's default

* refactor

* fix CI

* refactor

* refactor

* add tests

* fix tests

* remove unused file
diff --git a/knip.jsonc b/knip.jsonc
@@ -26,6 +26,8 @@
         "c8",
         // Optional peer dependency used for loading TypeScript configuration files
         "jiti",
+        "jiti-v2.0",
+        "jiti-v2.1",
       ],
     },
     "docs": {
diff --git a/lib/config/config-loader.js b/lib/config/config-loader.js
@@ -139,12 +139,13 @@ function isNativeTypeScriptSupportEnabled() {
  * @since 9.24.0
  */
 async function loadTypeScriptConfigFileWithJiti(filePath, fileURL, mtime) {
-	// eslint-disable-next-line no-use-before-define -- `ConfigLoader.loadJiti` can be overwritten for testing
-	const { createJiti } = await ConfigLoader.loadJiti().catch(() => {
-		throw new Error(
-			"The 'jiti' library is required for loading TypeScript configuration files. Make sure to install it.",
-		);
-	});
+	const { createJiti, version: jitiVersion } =
+		// eslint-disable-next-line no-use-before-define -- `ConfigLoader.loadJiti` can be overwritten for testing
+		await ConfigLoader.loadJiti().catch(() => {
+			throw new Error(
+				"The 'jiti' library is required for loading TypeScript configuration files. Make sure to install it.",
+			);
+		});
 
 	// `createJiti` was added in jiti v2.
 	if (typeof createJiti !== "function") {
@@ -157,11 +158,15 @@ async function loadTypeScriptConfigFileWithJiti(filePath, fileURL, mtime) {
 	 * Disabling `moduleCache` allows us to reload a
 	 * config file when the last modified timestamp changes.
 	 */
-
-	const jiti = createJiti(__filename, {
+	const jitiOptions = {
 		moduleCache: false,
-		interopDefault: false,
-	});
+	};
+
+	if (jitiVersion.startsWith("2.1.")) {
+		jitiOptions.interopDefault = false;
+	}
+
+	const jiti = createJiti(__filename, jitiOptions);
 	const config = await jiti.import(fileURL.href);
 
 	importedConfigFileModificationTime.set(filePath, mtime);
@@ -498,11 +503,12 @@ class ConfigLoader {
 
 	/**
 	 * Used to import the jiti dependency. This method is exposed internally for testing purposes.
-	 * @returns {Promise<Record<string, unknown>>} A promise that fulfills with a module object
-	 *      or rejects with an error if jiti is not found.
+	 * @returns {Promise<{createJiti: Function|undefined, version: string;}>} A promise that fulfills with an object containing the jiti module's createJiti function and version.
 	 */
-	static loadJiti() {
-		return import("jiti");
+	static async loadJiti() {
+		const { createJiti } = await import("jiti");
+		const version = require("jiti/package.json").version;
+		return { createJiti, version };
 	}
 
 	/**
diff --git a/package.json b/package.json
@@ -173,7 +173,9 @@
     "globals": "^15.0.0",
     "got": "^11.8.3",
     "gray-matter": "^4.0.3",
-    "jiti": "^2.1.0",
+    "jiti": "^2.2.0",
+    "jiti-v2.0": "npm:jiti@2.0.x",
+    "jiti-v2.1": "npm:jiti@2.1.x",
     "knip": "^5.32.0",
     "lint-staged": "^11.0.0",
     "load-perf": "^0.2.0",
diff --git a/tests/fixtures/ts-config-files/ts/jiti-interopDefault/foo.js b/tests/fixtures/ts-config-files/ts/jiti-interopDefault/foo.js
@@ -0,0 +1 @@
+foo;
diff --git a/tests/fixtures/ts-config-files/ts/jiti-interopDefault/plugin/index.js b/tests/fixtures/ts-config-files/ts/jiti-interopDefault/plugin/index.js
@@ -0,0 +1,12 @@
+module.exports = {
+    configs: {
+        recommended: {
+            rules: {
+                "no-undef": "error",
+            },
+        },
+    },
+};
+
+// The following string will confuse jiti when interopDefault is false:
+// @foo export {}
diff --git a/tests/fixtures/ts-config-files/ts/jiti-interopDefault/plugin/package.json b/tests/fixtures/ts-config-files/ts/jiti-interopDefault/plugin/package.json
@@ -0,0 +1,3 @@
+{
+    "type": "commonjs"
+}
diff --git a/tests/lib/eslint/eslint.js b/tests/lib/eslint/eslint.js
