feat: add dual module support (CommonJS + ESM)

jest.config.js

@@ -1,15 +1,12 @@
-module.exports = {
-    preset: 'ts-jest',
-    transform: { '^.+\\.ts': 'ts-jest' },
+export default {
+    preset: 'ts-jest/presets/default-esm',
+    extensionsToTreatAsEsm: ['.ts'],
+    transform: {
+        '^.+\\.ts$': ['ts-jest', { useESM: true }],
+    },
     testMatch: ['**/*.test.ts'],
     clearMocks: true,
     testEnvironment: 'node',
-    extensionsToTreatAsEsm: ['.ts'],
-    globals: {
-        'ts-jest': {
-            useESM: true,
-        },
-    },
     transformIgnorePatterns: [
         'node_modules/(?!(msw|@mswjs|@bundled-es-modules|until-async|chalk|@open-draft|@inquirer|strict-event-emitter)/)',
     ],

package.json

@@ -6,8 +6,17 @@
     "repository": "git@github.com:doist/todoist-api-typescript.git",
     "homepage": "https://doist.github.io/todoist-api-typescript/",
     "license": "MIT",
-    "main": "dist/index.js",
-    "types": "dist/index.d.ts",
+    "type": "module",
+    "main": "dist/cjs/index.js",
+    "module": "dist/esm/index.js",
+    "types": "dist/types/index.d.ts",
+    "exports": {
+        ".": {
+            "import": "./dist/esm/index.js",
+            "require": "./dist/cjs/index.js",
+            "types": "./dist/types/index.d.ts"
+        }
+    },
     "sideEffects": false,
     "engines": {
         "node": ">=20.0.0"
@@ -21,7 +30,11 @@
         "ts-compile-check": "npx tsc -p tsconfig.typecheck.json",
         "audit": "npm audit --audit-level=moderate",
         "test": "jest",
-        "build": "npx tsc -p tsconfig.json",
+        "build:cjs": "npx tsc -p tsconfig.cjs.json",
+        "build:esm": "npx tsc -p tsconfig.esm.json",
+        "build:fix-esm": "node scripts/fix-esm-imports.cjs",
+        "build:post": "echo '{\"type\":\"commonjs\"}' > dist/cjs/package.json",
+        "build": "npm-run-all clean build:cjs build:esm build:fix-esm build:post",
         "integrity-checks": "npm-run-all clean format-check lint-check test build",
         "prepublishOnly": "npm run integrity-checks",
         "prepare": "npm run build"
@@ -71,7 +84,9 @@
         "*.{ts,tsx,json,html,yml,yaml,md}": "prettier --check"
     },
     "files": [
-        "dist/**/*",
+        "dist/cjs/**/*",
+        "dist/esm/**/*",
+        "dist/types/**/*",
         "!dist/**/*.test.js",
         "!dist/**/*.test.d.ts"
     ]

scripts/fix-esm-imports.cjs

@@ -0,0 +1,99 @@
+#!/usr/bin/env node
+
+const fs = require('fs');
+const path = require('path');
+
+/**
+ * Post-build script to fix ESM imports by adding .js extensions.
+ * This is required because ESM requires explicit file extensions for relative imports.
+ */
+
+const ESM_DIR = path.join(__dirname, '../dist/esm');
+
+function fixImportsInFile(filePath) {
+    let content = fs.readFileSync(filePath, 'utf8');
+    let modified = false;
+
+    // Fix relative imports - add .js extension if missing
+    content = content.replace(
+        /from\s+['"](\.[^'"]*?)['"];?/g,
+        (match, importPath) => {
+            // Skip if already has extension or is directory import
+            if (path.extname(importPath) || importPath.endsWith('/')) {
+                return match;
+            }
+
+            // Check if this is a directory import (look for index file)
+            const fullPath = path.resolve(path.dirname(filePath), importPath);
+            const indexPath = path.join(fullPath, 'index.js');
+
+            if (fs.existsSync(indexPath)) {
+                // Directory import - add /index.js
+                modified = true;
+                return match.replace(importPath, importPath + '/index.js');
+            } else {
+                // File import - add .js
+                modified = true;
+                return match.replace(importPath, importPath + '.js');
+            }
+        }
+    );
+
+    // Fix export statements as well
+    content = content.replace(
+        /export\s+(?:\*|\{[^}]*\})\s+from\s+['"](\.[^'"]*?)['"];?/g,
+        (match, importPath) => {
+            // Skip if already has extension or is directory import
+            if (path.extname(importPath) || importPath.endsWith('/')) {
+                return match;
+            }
+
+            // Check if this is a directory import (look for index file)
+            const fullPath = path.resolve(path.dirname(filePath), importPath);
+            const indexPath = path.join(fullPath, 'index.js');
+
+            if (fs.existsSync(indexPath)) {
+                // Directory import - add /index.js
+                modified = true;
+                return match.replace(importPath, importPath + '/index.js');
+            } else {
+                // File import - add .js
+                modified = true;
+                return match.replace(importPath, importPath + '.js');
+            }
+        }
+    );
+
+    if (modified) {
+        fs.writeFileSync(filePath, content, 'utf8');
+        console.log(`Fixed imports in: ${path.relative(process.cwd(), filePath)}`);
+    }
+}
+
+function walkDirectory(dir) {
+    const files = fs.readdirSync(dir);
+
+    for (const file of files) {
+        const filePath = path.join(dir, file);
+        const stat = fs.statSync(filePath);
+
+        if (stat.isDirectory()) {
+            walkDirectory(filePath);
+        } else if (file.endsWith('.js')) {
+            fixImportsInFile(filePath);
+        }
+    }
+}
+
+function main() {
+    if (!fs.existsSync(ESM_DIR)) {
+        console.log('ESM directory does not exist, skipping import fixing');
+        return;
+    }
+
+    console.log('Fixing ESM imports by adding .js extensions...');
+    walkDirectory(ESM_DIR);
+    console.log('ESM import fixing completed');
+}
+
+main();

tsconfig.cjs.json

@@ -0,0 +1,9 @@
+{
+    "extends": "./tsconfig.json",
+    "compilerOptions": {
+        "module": "commonjs",
+        "outDir": "dist/cjs",
+        "declaration": true,
+        "declarationDir": "dist/types"
+    }
+}

tsconfig.esm.json

@@ -0,0 +1,9 @@
+{
+    "extends": "./tsconfig.json",
+    "compilerOptions": {
+        "module": "esnext",
+        "moduleResolution": "bundler",
+        "outDir": "dist/esm",
+        "declaration": false
+    }
+}