[Fix] no-duplicates: do not unconditionally require typescript

Fixes #2665

Author: ljharb

CHANGELOG.md

@@ -6,6 +6,9 @@ This change log adheres to standards from [Keep a CHANGELOG](https://keepachange
 
 ## [Unreleased]
 
+### Fixed
+- [`no-duplicates`]: do not unconditionally require `typescript` ([#2665])
+
 ## [2.27.1] - 2023-01-11
 
 ### Fixed
@@ -1361,6 +1364,7 @@ for info on changes for earlier releases.
 [#211]: https://github.com/import-js/eslint-plugin-import/pull/211
 [#164]: https://github.com/import-js/eslint-plugin-import/pull/164
 [#157]: https://github.com/import-js/eslint-plugin-import/pull/157
+[#2665]: https://github.com/import-js/eslint-plugin-import/issues/2665
 [#2444]: https://github.com/import-js/eslint-plugin-import/issues/2444
 [#2412]: https://github.com/import-js/eslint-plugin-import/issues/2412
 [#2392]: https://github.com/import-js/eslint-plugin-import/issues/2392

src/rules/no-duplicates.js

@@ -1,7 +1,11 @@
 import resolve from 'eslint-module-utils/resolve';
 import docsUrl from '../docsUrl';
 import semver from 'semver';
-import typescriptPkg from 'typescript/package.json';
+
+let typescriptPkg;
+try {
+  typescriptPkg = require('typescript/package.json');
+} catch (e) { /**/ }
 
 function checkImports(imported, context) {
   for (const [module, nodes] of imported.entries()) {
@@ -114,7 +118,7 @@ function getFix(first, rest, sourceCode, context) {
 
         const preferInline = context.options[0] && context.options[0]['prefer-inline'];
         // a user might set prefer-inline but not have a supporting TypeScript version.  Flow does not support inline types so this should fail in that case as well.
-        if (preferInline && !semver.satisfies(typescriptPkg.version, '>= 4.5')) {
+        if (preferInline && (!typescriptPkg || !semver.satisfies(typescriptPkg.version, '>= 4.5'))) {
           throw new Error('Your version of TypeScript does not support inline type imports.');
         }