Fix jest config

Author: nicolo-ribaudo

jest.config.js

@@ -1,9 +1,8 @@
 /** @type {import('ts-jest/dist/types').InitialOptionsTsJest} */
 
-const runNatively = !!process.features.typescript;
+const nativeESM = !!process.features.typescript;
 
-module.exports = {
-  runner: runNatively ? 'jest-light-runner' : undefined,
+const config = {
   preset: 'ts-jest/presets/default-esm',
   testEnvironment: 'node',
   moduleDirectories: ['node_modules', 'src'],
@@ -13,7 +12,13 @@ module.exports = {
       diagnostics: {
         ignoreCodes: [151001],
       },
-      useESM: runNatively,
+      useESM: nativeESM,
     },
   },
 };
+
+if (nativeESM) {
+  config.runner = 'jest-light-runner';
+}
+
+module.exports = config;