[Fix] no-unused-modules: avoid a crash when processing re-exports

Fixes #2388.

Author: ljharb

CHANGELOG.md

@@ -15,6 +15,7 @@ This change log adheres to standards from [Keep a CHANGELOG](https://keepachange
 - [`default`]: `typescript-eslint-parser`: avoid a crash on exporting as namespace (thanks [@ljharb])
 - [`export`]/TypeScript: false positive for typescript namespace merging ([#1964], thanks [@magarcia])
 - [`no-duplicates`]: ignore duplicate modules in different TypeScript module declarations ([#2378], thanks [@remcohaszing])
+- [`no-unused-modules`]: avoid a crash when processing re-exports ([#2388], thanks [@ljharb])
 
 ### Changed
 - [Tests] `no-nodejs-modules`: add tests for node protocol URL ([#2367], thanks [@sosukesuzuki])
@@ -973,6 +974,7 @@ for info on changes for earlier releases.
 [`memo-parser`]: ./memo-parser/README.md
 
 [#2393]: https://github.com/import-js/eslint-plugin-import/pull/2393
+[#2388]: https://github.com/import-js/eslint-plugin-import/pull/2388
 [#2381]: https://github.com/import-js/eslint-plugin-import/pull/2381
 [#2378]: https://github.com/import-js/eslint-plugin-import/pull/2378
 [#2371]: https://github.com/import-js/eslint-plugin-import/pull/2371

src/rules/no-unused-modules.js

@@ -273,8 +273,10 @@ const prepareImportsAndExports = (srcFiles, context) => {
   exportAll.forEach((value, key) => {
     value.forEach(val => {
       const currentExports = exportList.get(val);
-      const currentExport = currentExports.get(EXPORT_ALL_DECLARATION);
-      currentExport.whereUsed.add(key);
+      if (currentExports) {
+        const currentExport = currentExports.get(EXPORT_ALL_DECLARATION);
+        currentExport.whereUsed.add(key);
+      }
     });
   });
 };

tests/files/unused-modules-reexport-crash/src/App.tsx

@@ -0,0 +1,5 @@
+import { hello } from './magic/test'
+
+hello();
+
+export default function App() {};

tests/files/unused-modules-reexport-crash/src/index.tsx

@@ -0,0 +1,3 @@
+import App from './App';
+
+export const x = App

tests/files/unused-modules-reexport-crash/src/magic/index.js

@@ -0,0 +1 @@
+export * from './test'

tests/files/unused-modules-reexport-crash/src/magic/test.js

@@ -0,0 +1,7 @@
+export function hello() {
+	console.log('hello!!');
+}
+
+export function unused() {
+	console.log('im unused!!');
+}

tests/src/rules/no-unused-modules.js

@@ -105,7 +105,7 @@ ruleTester.run('no-unused-modules', rule, {
 });
 
 
-// tests for  exports
+// tests for exports
 ruleTester.run('no-unused-modules', rule, {
   valid: [
     test({
@@ -301,6 +301,17 @@ describe('dynamic imports', () => {
         parser: parsers.TS_NEW,
         filename: testFilePath('./no-unused-modules/typescript/exports-for-dynamic-ts.ts'),
       }),
+      test({
+        code: `
+        import App from './App';
+      `,
+        filename: testFilePath('./unused-modules-reexport-crash/src/index.tsx'),
+        parser: parsers.TS_NEW,
+        options: [{        
+          unusedExports: true,
+          ignoreExports: ['**/magic/**'],
+        }],
+      }),
     ],
     invalid: [
     ],