feat: drop support for jiti v1.21 (#18996)

* feat: drop support for jiti v1.21

* fix for CommonJS TS config that exports undefined

docs/src/use/configure/configuration-files.md

@@ -529,7 +529,7 @@ npx eslint --flag unstable_ts_config
 
 For more information about using feature flags, see [Feature Flags](../../flags/).
 
-For Deno and Bun, TypeScript configuration files are natively supported; for Node.js, you must install the optional dev dependency [`jiti`](https://github.com/unjs/jiti) in your project (this dependency is not automatically installed by ESLint):
+For Deno and Bun, TypeScript configuration files are natively supported; for Node.js, you must install the optional dev dependency [`jiti`](https://github.com/unjs/jiti) in version 2.0.0 or later in your project (this dependency is not automatically installed by ESLint):
 
 ```bash
 npm install -D jiti

lib/config/config-loader.js

@@ -173,21 +173,22 @@ async function loadConfigFile(filePath, allowTS) {
  */
  if (allowTS && isTS && !isDeno && !isBun) {
 
- const createJiti = await import("jiti").then(jitiModule => (typeof jitiModule?.createJiti === "function" ? jitiModule.createJiti : jitiModule.default), () => {
+ // 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.");
  });
 
+ // `createJiti` was added in jiti v2.
+ if (typeof createJiti !== "function") {
+ throw new Error("You are using an outdated version of the 'jiti' library. Please update to the latest version of 'jiti' to ensure compatibility and access to the latest features.");
+ }
+
  /*
  * Disabling `moduleCache` allows us to reload a
  * config file when the last modified timestamp changes.
  */
 
  const jiti = createJiti(__filename, { moduleCache: false, interopDefault: false });
-
- if (typeof jiti?.import !== "function") {
- throw new Error("You are using an outdated version of the 'jiti' library. Please update to the latest version of 'jiti' to ensure compatibility and access to the latest features.");
- }
-
  const config = await jiti.import(fileURL.href);
 
  importedConfigFileModificationTime.set(filePath, mtime);
@@ -294,7 +295,6 @@ async function calculateConfigArray(configFilePath, basePath, options) {
  return configs;
 }
 
-
 //-----------------------------------------------------------------------------
 // Exports
 //-----------------------------------------------------------------------------
@@ -517,6 +517,15 @@ class ConfigLoader {
  return this.#configArrays.get(configFilePath);
  }
 
+ /**
+ * 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.
+ */
+ static loadJiti() {
+ return import("jiti");
+ }
+
 }
 
 /**

tests/fixtures/ts-config-files/ts/eslint.undefined.config.ts

@@ -0,0 +1 @@
+export = void 0;

tests/lib/eslint/eslint.js

@@ -1313,6 +1313,61 @@ describe("ESLint", () => {
 
  });
 
+ it("should fail to load a TS config file if jiti is not installed", async () => {
+
+ const { ConfigLoader } = require("../../../lib/config/config-loader");
+
+ sinon.stub(ConfigLoader, "loadJiti").rejects();
+
+ const cwd = getFixturePath("ts-config-files", "ts");
+
+ eslint = new ESLint({
+ cwd,
+ flags: tsFlags
+ });
+
+ await assert.rejects(
+ eslint.lintText("foo();"),
+ { message: "The 'jiti' library is required for loading TypeScript configuration files. Make sure to install it." }
+ );
+ });
+
+ it("should fail to load a TS config file if an outdated version of jiti is installed", async () => {
+
+ const { ConfigLoader } = require("../../../lib/config/config-loader");
+
+ sinon.stub(ConfigLoader, "loadJiti").resolves({});
+
+ const cwd = getFixturePath("ts-config-files", "ts");
+
+ eslint = new ESLint({
+ cwd,
+ flags: tsFlags
+ });
+
+ await assert.rejects(
+ eslint.lintText("foo();"),
+ { message: "You are using an outdated version of the 'jiti' library. Please update to the latest version of 'jiti' to ensure compatibility and access to the latest features." }
+ );
+ });
+
+ it("should fail to load a CommonJS TS config file that exports undefined with a helpful error message", async () => {
+
+ const cwd = getFixturePath("ts-config-files", "ts");
+
+ eslint = new ESLint({
+ cwd,
+ flags: tsFlags,
+ overrideConfigFile: "eslint.undefined.config.ts"
+ });
+
+ await assert.rejects(
+ eslint.lintText("foo"),
+ { message: "Config (unnamed): Unexpected undefined config at user-defined index 0." }
+ );
+
+ });
+
  });
 
  it("should pass BOM through processors", async () => {
@@ -5753,6 +5808,61 @@ describe("ESLint", () => {
 
  });
 
+ it("should fail to load a TS config file if jiti is not installed", async () => {
+
+ const { ConfigLoader } = require("../../../lib/config/config-loader");
+
+ sinon.stub(ConfigLoader, "loadJiti").rejects();
+
+ const cwd = getFixturePath("ts-config-files", "ts");
+
+ eslint = new ESLint({
+ cwd,
+ flags: newFlags
+ });
+
+ await assert.rejects(
+ eslint.lintFiles("foo.js"),
+ { message: "The 'jiti' library is required for loading TypeScript configuration files. Make sure to install it." }
+ );
+ });
+
+ it("should fail to load a TS config file if an outdated version of jiti is installed", async () => {
+
+ const { ConfigLoader } = require("../../../lib/config/config-loader");
+
+ sinon.stub(ConfigLoader, "loadJiti").resolves({});
+
+ const cwd = getFixturePath("ts-config-files", "ts");
+
+ eslint = new ESLint({
+ cwd,
+ flags: newFlags
+ });
+
+ await assert.rejects(
+ eslint.lintFiles("foo.js"),
+ { message: "You are using an outdated version of the 'jiti' library. Please update to the latest version of 'jiti' to ensure compatibility and access to the latest features." }
+ );
+ });
+
+ it("should fail to load a CommonJS TS config file that exports undefined with a helpful error message", async () => {
+
+ const cwd = getFixturePath("ts-config-files", "ts");
+
+ eslint = new ESLint({
+ cwd,
+ flags: newFlags,
+ overrideConfigFile: "eslint.undefined.config.ts"
+ });
+
+ await assert.rejects(
+ eslint.lintFiles("foo.js"),
+ { message: "Config (unnamed): Unexpected undefined config at user-defined index 0." }
+ );
+
+ });
+
  });
 
  it("should stop linting files if a rule crashes", async () => {