Modify unit test to compile ESM syntax

- Added function `pathsToESModuleNameMapper` to resolve relative import syntax
with file extension.
- Disabled ESLint rule 'import/no-extraneous-dependencies' for unit test files.
- Appended file extenion `.js` for relative import in `main.spec.ts`.

Author: iamWing

.eslintrc.cjs

@@ -79,6 +79,7 @@ const jestConfig = {
   ],
   rules: {
     ...tsConfig.rules,
+    'import/no-extraneous-dependencies': 'off',
     '@typescript-eslint/no-non-null-assertion': 'off',
   },
   settings: tsConfig.settings,

jest.config.js

@@ -4,6 +4,33 @@ import { pathsToModuleNameMapper } from 'ts-jest';
 const require = createRequire(import.meta.url);
 const { compilerOptions } = require('./tsconfig.json');
 
+/**
+ * Enhance the Jest path mappings map returned from `pathsModuleNameMapper`
+ * to support ES modules import syntax in TypeScript.
+ *
+ * @returns Jest path mappings map.
+ */
+function pathsToESMModuleNameMapper() {
+  const map = pathsToModuleNameMapper(
+    compilerOptions.paths,
+    { prefix: '<rootDir>' },
+  );
+  const esmMap = {};
+
+  Object.entries(map).forEach((entry) => {
+    const [key, val] = entry;
+
+    if (/.*\(\.\*\)\$$/.test(key)) {
+      const convertedKey = `${key.substring(0, key.length - 1)}\\.js$`;
+      esmMap[convertedKey] = val;
+    }
+
+    esmMap[key] = val;
+  });
+
+  return esmMap;
+}
+
 export default {
   testEnvironment: 'node',
   globals: {
@@ -12,10 +39,7 @@ export default {
     },
   },
   moduleFileExtensions: ['ts', 'tsx', 'js', 'jsx', 'json'],
-  moduleNameMapper: pathsToModuleNameMapper(
-    compilerOptions.paths,
-    { prefix: '<rootDir>/' },
-  ),
+  moduleNameMapper: pathsToESMModuleNameMapper(),
   modulePathIgnorePatterns: [
     '<rootDir>/dist',
     '<rootDir>/node_modules',

tests/main/main.spec.ts

@@ -1,5 +1,6 @@
+import { jest } from '@jest/globals';
 import { BrowserWindow } from 'electron';
-import { exportedForTests } from '_main/main';
+import { exportedForTests } from '_main/main.js';
 
 jest.mock('electron', () => ({
   app: {