Repository: un-ts/eslint-plugin-import-x (ts)

Issue:
Replacing the built-in default import resolver that supports `exports` and `imports` from `package.json`
`eslint-plugin-import-x` has `eslint-import-resolver-node` as a dependency. When no resolver is specified in the eslint config, the `eslint-import-resolver-node` will be used. However, `eslint-import-resolver-node` doesn't support `exports` and `imports` from `package.json` and @ljharb ~~simply refuses~~ doesn't have time to implement this feature and even locks the feature request issue, see https://github.com/import-js/eslint-plugin-import/issues/1810.

So our plan is to abandon the `eslint-import-resolver-node`. We will be building a new eslint import resolver upon ~~[`@dual-bundle/import-meta-resolve`](https://www.npmjs.com/package/@dual-bundle/import-meta-resolve)~~ [`enhanced-resolve`](https://www.npmjs.com/package/enhanced-resolve). We will ship it with `eslint-plugin-import-x` and it will be an interface v3-only resolver.

In the next major version of `eslint-plugin-import-x`, we will remove `eslint-import-resolver-node` in favor of our own default resolver.

Pull request description:
feat: implement a resolver that supports `exports`
The PR implements a default resolver that supports `exports` from `package.json`.

More details can be found at #208.

Fixes #208.

Patch:
diff --git a/.changeset/witty-garlics-destroy.md b/.changeset/witty-garlics-destroy.md
new file mode 100644
index 00000000..ac826a23
--- /dev/null
+++ b/.changeset/witty-garlics-destroy.md
@@ -0,0 +1,52 @@
+---
+"eslint-plugin-import-x": minor
+---
+
+When `eslint-plugin-import-x` was forked from `eslint-plugin-import`, we copied over the default resolver (which is `eslint-import-resolver-node`) as well. However, this resolver doesn't supports `exports` in the `package.json` file, and the current maintainer of the `eslint-import-resolver-node` (ljharb) doesn't have the time implementing this feature and he locked the issue https://github.com/import-js/eslint-plugin-import/issues/1810.
+
+So we decided to implement our own resolver that "just works". The new resolver is built upon the [`enhanced-resolve`](https://www.npmjs.com/package/enhanced-resolve) that implements the full Node.js [Resolver Algorithm](https://nodejs.org/dist/v14.21.3/docs/api/esm.html#esm_resolver_algorithm). The new resolver only implements the import resolver interface v3, which means you can only use it with ESLint Flat config. For more details about the import resolver interface v3, please check out [#192](https://github.com/un-ts/eslint-plugin-import-x/pull/192).
+
+In the next major version of `eslint-plugin-import-x`, we will remove the `eslint-import-resolver-node` and use this new resolver by default. In the meantime, you can try out this new resolver by setting the `import-x/resolver-next` option in your `eslint.config.js` file:
+
+```js
+// eslint.config.js
+const eslintPluginImportX = require('eslint-plugin-import-x');
+const { createNodeResolver } = eslintPluginImportX;
+
+module.exports = {
+  plugins: {
+    'import-x': eslintPluginImportX,
+  },
+  settings: {
+    'import-x/resolver-next': [
+      // This is the new resolver we are introducing
+      createNodeResolver({
+        /**
+         * The allowed extensions the resolver will attempt to find when resolving a module
+         * By default it uses a relaxed extension list to search for both ESM and CJS modules
+         * You can customize this list to fit your needs
+         *
+         * @default ['.mjs', '.cjs', '.js', '.json', '.node']
+         */
+        extensions?: string[];
+        /**
+         * Optional, the import conditions the resolver will used when reading the exports map from "package.json"
+         * By default it uses a relaxed condition list to search for both ESM and CJS modules
+         * You can customize this list to fit your needs
+         *
+         * @default ['default', 'module', 'import', 'require']
+         */
+        conditions: ['default', 'module', 'import', 'require'],
+        // You can pass more options here, see the enhanced-resolve documentation for more details
+        // https://github.com/webpack/enhanced-resolve/tree/v5.17.1?tab=readme-ov-file#resolver-options
+      }),
+      // you can add more resolvers down below
+      require('eslint-import-resolver-typescript').createTypeScriptImportResolver(
+        /** options of eslint-import-resolver-typescript */
+      )
+    ],
+  },
+};
+```
+
+We do not plan to implement reading `baseUrl` and `paths` from the `tsconfig.json` file in this resolver. If you need this feature, please checkout [eslint-import-resolver-typescript](https://www.npmjs.com/package/eslint-import-resolver-typescript) (also powered by `enhanced-resolve`), [eslint-import-resolver-oxc](https://www.npmjs.com/package/eslint-import-resolver-oxc) (powered by `oxc-resolver`), [eslint-import-resolver-next](https://www.npmjs.com/package/eslint-import-resolver-next) (also powered by `oxc-resolver`), or other similar resolvers.
diff --git a/package.json b/package.json
index 6c715999..3029b14a 100644
--- a/package.json
+++ b/package.json
@@ -96,7 +96,7 @@
     "@typescript-eslint/rule-tester": "^8.15.0",
     "@unts/patch-package": "^8.0.0",
     "cross-env": "^7.0.3",
-    "enhanced-resolve": "^5.16.0",
+    "enhanced-resolve": "^5.17.1",
     "escope": "^4.0.0",
     "eslint": "^9.15.0",
     "eslint-config-prettier": "^9.1.0",
diff --git a/src/index.ts b/src/index.ts
index 5d34ef1b..bf7a43c3 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -72,6 +72,7 @@ import type {
   PluginFlatConfig,
 } from './types'
 import { importXResolverCompat } from './utils'
+import { createNodeResolver } from './node-resolver'
 
 const rules = {
   'no-unresolved': noUnresolved,
@@ -183,4 +184,5 @@ export = {
   flatConfigs,
   rules,
   importXResolverCompat,
+  createNodeResolver
 }
diff --git a/src/node-resolver.ts b/src/node-resolver.ts
new file mode 100644
index 00000000..9b0e6b34
--- /dev/null
+++ b/src/node-resolver.ts
@@ -0,0 +1,68 @@
+import { ResolverFactory, CachedInputFileSystem, type ResolveOptions } from 'enhanced-resolve';
+import fs from 'node:fs';
+import type { NewResolver } from './types';
+import { isBuiltin } from 'node:module';
+import { dirname } from 'node:path';
+
+interface NodeResolverOptions extends Omit<ResolveOptions, 'useSyncFileSystemCalls'> {
+  /**
+   * The allowed extensions the resolver will attempt to find when resolving a module
+   * @type {string[] | undefined}
+   * @default ['.mjs', '.cjs', '.js', '.json', '.node']
+   */
+  extensions?: string[];
+  /**
+   * The import conditions the resolver will used when reading the exports map from "package.json"
+   * @type {string[] | undefined}
+   * @default ['default', 'module', 'import', 'require']
+   */
+  conditionNames?: string[];
+}
+
+export function createNodeResolver({
+  extensions = ['.mjs', '.cjs', '.js', '.json', '.node'],
+  conditionNames = ['default', 'module', 'import', 'require'],
+  mainFields = ['main'],
+  exportsFields = ['exports'],
+  mainFiles = ['index'],
+  fileSystem = new CachedInputFileSystem(fs, 4 * 1000),
+  ...restOptions
+}: Partial<NodeResolverOptions> = {}): NewResolver {
+  const resolver = ResolverFactory.createResolver({
+    extensions,
+    fileSystem,
+    conditionNames,
+    useSyncFileSystemCalls: true,
+    ...restOptions,
+  });
+
+  // shared context across all resolve calls
+
+  return {
+    interfaceVersion: 3,
+    name: 'eslint-plugin-import-x built-in node resolver',
+    resolve: (modulePath, sourceFile) => {
+      if (isBuiltin(modulePath)) {
+        return { found: true, path: null };
+      }
+
+      if (modulePath.startsWith('data:')) {
+        return { found: true, path: null };
+      }
+
+      try {
+        const path = resolver.resolveSync(
+          {},
+          dirname(sourceFile),
+          modulePath
+        );
+        if (path) {
+          return { found: true, path };
+        }
+        return { found: false };
+      } catch {
+        return { found: false };
+      }
+    }
+  }
+}
diff --git a/yarn.lock b/yarn.lock
index dfe2a1bd..258fe862 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -3413,7 +3413,7 @@ enhanced-resolve@^0.9.1:
     memory-fs "^0.2.0"
     tapable "^0.1.8"
 
-enhanced-resolve@^5.12.0, enhanced-resolve@^5.16.0:
+enhanced-resolve@^5.12.0:
   version "5.16.0"
   resolved "https://registry.yarnpkg.com/enhanced-resolve/-/enhanced-resolve-5.16.0.tgz#65ec88778083056cb32487faa9aef82ed0864787"
   integrity sha512-O+QWCviPNSSLAD9Ucn8Awv+poAkqn3T1XY5/N7kR7rQO9yfSGWkYZDwpJ+iKF7B8rxaQKWngSqACpgzeapSyoA==
@@ -3421,6 +3421,14 @@ enhanced-resolve@^5.12.0, enhanced-resolve@^5.16.0:
     graceful-fs "^4.2.4"
     tapable "^2.2.0"
 
+enhanced-resolve@^5.17.1:
+  version "5.17.1"
+  resolved "https://registry.yarnpkg.com/enhanced-resolve/-/enhanced-resolve-5.17.1.tgz#67bfbbcc2f81d511be77d686a90267ef7f898a15"
+  integrity sha512-LMHl3dXhTcfv8gM4kEzIUeTQ+7fpdA0l2tUf34BddXPkz2A5xJ5L/Pchd5BL6rdccM9QGvu0sWZzK1Z1t4wwyg==
+  dependencies:
+    graceful-fs "^4.2.4"
+    tapable "^2.2.0"
+
 enquirer@^2.3.0:
   version "2.4.1"
   resolved "https://registry.yarnpkg.com/enquirer/-/enquirer-2.4.1.tgz#93334b3fbd74fc7097b224ab4a8fb7e40bf4ae56"


Test patch:
diff --git a/test/node-resolver.spec.ts b/test/node-resolver.spec.ts
new file mode 100644
index 00000000..12bb7355
--- /dev/null
+++ b/test/node-resolver.spec.ts
@@ -0,0 +1,45 @@
+import path from 'node:path'
+import { cwd } from 'node:process'
+import { createNodeResolver } from '../src/node-resolver';
+
+const resolver = createNodeResolver()
+
+function expectResolve(source: string, expected: boolean | string) {
+  it(`${source} => ${expected}`, () => {
+    try {
+      console.log({ source, expected, requireResolve: require.resolve(source, { paths: [__dirname] }) })
+
+    } catch {
+      console.log({ source, expected, requireResolve: null })
+    }
+    const result = resolver.resolve(source, __filename);
+    console.log({ source, expected, result })
+
+    if (typeof expected === 'string') {
+      expect(result.path).toBe(path.resolve(cwd(), expected))
+    } else {
+      expect(result.found).toBe(expected)
+    }
+  })
+}
+
+describe('builtin', () => {
+  expectResolve('path', true)
+  expectResolve('node:path', true)
+})
+
+describe('modules', () => {
+  expectResolve('jest', true)
+  expectResolve('@sukka/does-not-exists', false)
+})
+
+describe('relative', () => {
+  expectResolve('../package.json', 'package.json')
+  expectResolve('../.github/dependabot.yml', false)
+  expectResolve('../babel.config.js', 'babel.config.js')
+  expectResolve('../test/index.js', 'test/index.js')
+  expectResolve('../test/', 'test/index.js')
+  expectResolve('../test', 'test/index.js')
+
+  expectResolve('../inexistent.js', false)
+})