fix: resolve CJS build issue causing "TypeError: Nylas is not a constructor" error

CHANGELOG.md

@@ -5,6 +5,11 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+### Fixed
+- Broken CJS build outputs resulted in a "TypeError: Nylas is not a constructor" error
+
 ## [7.13.0] - 2025-09-01
 
 ### Added

cjs-wrapper.d.ts

@@ -0,0 +1,14 @@
+/**
+ * TypeScript definitions for the CommonJS wrapper
+ * This provides proper typing for CommonJS imports
+ */
+
+// Re-export all types from the main module
+export * from './lib/types/models/index.js';
+
+// Import the main Nylas class type
+import Nylas from './lib/types/nylas.js';
+
+// Export as both default and named for maximum compatibility
+declare const nylasExport: typeof Nylas;
+export = nylasExport;

cjs-wrapper.js

@@ -0,0 +1,13 @@
+/**
+ * CommonJS wrapper for the Nylas SDK
+ * This file provides CommonJS compatibility by re-exporting the default export
+ * as the main module export while preserving named exports
+ */
+
+const nylasModule = require('./lib/cjs/nylas.js');
+
+// Export the default export as the main module export for CJS compatibility
+module.exports = nylasModule.default;
+
+// Preserve all named exports
+Object.assign(module.exports, nylasModule);

examples/cjs-only/README.md

@@ -0,0 +1,78 @@
+# CommonJS-Only Nylas SDK Example
+
+This example demonstrates how to use the Nylas Node.js SDK in a pure CommonJS (CJS) environment without ES module syntax.
+
+## Purpose
+
+- Shows CommonJS `require()` syntax with the Nylas SDK
+- Demonstrates environment variable handling in CommonJS
+- Provides a simple messages listing example
+- Serves as a reference for projects that must use CommonJS
+
+## Key Differences from ESM
+
+This example showcases the CommonJS equivalent of the ESM-only example:
+
+| ESM Syntax | CommonJS Syntax |
+|------------|-----------------|
+| `import Nylas from 'nylas'` | `const Nylas = require('nylas')` |
+| `import dotenv from 'dotenv'` | `const dotenv = require('dotenv')` |
+| `import path from 'node:path'` | `const path = require('path')` |
+| `import.meta.dirname` | `__dirname` |
+| `export { logger }` | `module.exports = { logger }` |
+
+## Setup
+
+1. **Install dependencies:**
+   ```bash
+   cd examples/cjs-only
+   npm install
+   ```
+
+2. **Set up environment variables:**
+   - Copy `examples/.env.example` to `examples/.env`
+   - Fill in your `NYLAS_API_KEY` and `NYLAS_GRANT_ID`
+
+3. **Run the example:**
+   ```bash
+   npm start
+   # or
+   node index.js
+   ```
+
+## Requirements
+
+- Node.js (any version - CommonJS is supported in all Node.js versions)
+- Valid Nylas API credentials
+- A grant with message access permissions
+
+## What This Example Does
+
+1. Loads environment variables using `dotenv`
+2. Validates required API credentials
+3. Initializes the Nylas client
+4. Lists messages from the specified grant
+5. Logs the results with proper error handling
+
+## File Structure
+
+```
+cjs-only/
+├── index.js          # Main example file (CommonJS)
+├── package.json      # Package configuration (no "type": "module")
+├── utils/
+│   └── logger.js     # Logger utility (CommonJS exports)
+└── README.md         # This file
+```
+
+## Troubleshooting
+
+- **"NYLAS_API_KEY environment variable is not set"**: Make sure you've created the `.env` file in the `examples/` directory with your API key
+- **"NYLAS_GRANT_ID environment variable is not set"**: Add your grant ID to the `.env` file
+- **Module not found errors**: Run `npm install` to install dependencies
+- **Permission errors**: Ensure your API key and grant have the necessary permissions to list messages
+
+## Related Examples
+
+- `../esm-only/` - ESM version of this same example
+- `../messages/` - More comprehensive message handling examples

examples/cjs-only/index.js

@@ -0,0 +1,82 @@
+/**
+ * CommonJS-Only Nylas SDK Example
+ *
+ * This example demonstrates how to use the Nylas Node.js SDK in a pure CommonJS
+ * (CJS) environment without ES module syntax.
+ *
+ * Purpose:
+ * - Shows CommonJS require() syntax with the Nylas SDK
+ * - Demonstrates environment variable handling in CommonJS
+ * - Provides a simple messages listing example
+ *
+ * Usage:
+ * 1. Copy the parent examples/.env.example to examples/.env
+ * 2. Fill in your NYLAS_API_KEY and NYLAS_GRANT_ID in the .env file
+ * 3. Run: node index.js (or npm start)
+ *
+ * Requirements:
+ * - Node.js with CommonJS support (any Node.js version)
+ * - Valid Nylas API credentials
+ * - A grant with message access permissions
+ */
+
+const dotenv = require('dotenv');
+const path = require('path');
+const Nylas = require('nylas');
+const { logger, maskSecret } = require('./utils/logger.js');
+
+// Load from parent directory since this example lives in a subdirectory
+dotenv.config({ path: path.resolve(__dirname, '../.env') });
+
+// Fail fast if credentials are missing to provide clear error messages
+const apiKey = process.env.NYLAS_API_KEY || '';
+if (!apiKey) {
+  throw new Error('NYLAS_API_KEY environment variable is not set');
+}
+
+const grantId = process.env.NYLAS_GRANT_ID || '';
+if (!grantId) {
+  throw new Error('NYLAS_GRANT_ID environment variable is not set');
+}
+
+// Initialize the Nylas client
+const nylas = new Nylas({
+  apiKey,
+  apiUri: process.env.NYLAS_API_URI || 'https://api.us.nylas.com',
+});
+
+/**
+ * Main function to demonstrate basic Nylas SDK usage in CommonJS environment
+ */
+async function main() {
+  try {
+    logger.info('Listing messages...');
+
+    // Log runtime config for debugging without exposing sensitive data
+    logger.debug('Runtime config', {
+      apiKey: maskSecret(apiKey),
+      grantId,
+      apiUri: process.env.NYLAS_API_URI || 'https://api.us.nylas.com',
+    });
+
+    // Use basic list operation to verify SDK functionality and connectivity
+    const messages = await nylas.messages.list({
+      identifier: grantId,
+    });
+
+    logger.success('Messages listed successfully');
+
+    // Extract only essential fields to avoid logging sensitive message content
+    logger.info(
+      'Message subjects and ids',
+      messages.data.map((m) => ({ id: m.id, subject: m.subject }))
+    );
+  } catch (error) {
+    logger.error('Failed to list messages');
+    logger.debug('Error details', error);
+    // Exit with error code to indicate failure for automation/CI purposes
+    process.exit(1);
+  }
+}
+
+main();

examples/cjs-only/package.json

@@ -0,0 +1,16 @@
+{
+  "name": "cjs-only",
+  "version": "1.0.0",
+  "description": "A CommonJS-only example of the Nylas NodeJS SDK usage",
+  "main": "index.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1",
+    "start": "node index.js"
+  },
+  "author": "",
+  "license": "ISC",
+  "dependencies": {
+    "nylas": "file:../../",
+    "dotenv": "^17.2.2"
+  }
+}

examples/cjs-only/utils/logger.js

@@ -0,0 +1,46 @@
+// Pretty logger for CommonJS
+const COLORS = {
+  reset: '\x1b[0m',
+  dim: '\x1b[2m',
+  gray: '\x1b[90m',
+  bold: '\x1b[1m',
+  info: '\x1b[36m',
+  success: '\x1b[32m',
+  warn: '\x1b[33m',
+  error: '\x1b[31m',
+  debug: '\x1b[35m',
+};
+
+function ts() {
+  return new Date().toISOString();
+}
+
+function maskSecret(value, visibleStart = 8, visibleEnd = 0) {
+  if (!value) return '';
+  const start = value.slice(0, visibleStart);
+  const end = visibleEnd ? value.slice(-visibleEnd) : '';
+  const hidden = Math.max(0, value.length - start.length - end.length);
+  return `${start}${'•'.repeat(hidden)}${end}`;
+}
+
+function print(level, symbol, message, meta) {
+  const color = COLORS[level] || COLORS.info;
+  const time = `${COLORS.dim}${ts()}${COLORS.reset}`;
+  const label = `${color}${symbol} ${level.toUpperCase()}${COLORS.reset}`;
+  const line =
+    typeof message === 'string' ? message : JSON.stringify(message, null, 2);
+  console.log(`${time} ${label} ${line}`);
+  if (meta !== undefined) {
+    console.dir(meta, { depth: null, colors: true, maxArrayLength: 100 });
+  }
+}
+
+const logger = {
+  info: (msg, meta) => print('info', 'ℹ', msg, meta),
+  success: (msg, meta) => print('success', '✔', msg, meta),
+  warn: (msg, meta) => print('warn', '⚠', msg, meta),
+  error: (msg, meta) => print('error', '✖', msg, meta),
+  debug: (msg, meta) => print('debug', '🐛', msg, meta),
+};
+
+module.exports = { logger, maskSecret };

package.json

@@ -72,8 +72,13 @@
     "url": "https://github.com/nylas/nylas-nodejs.git"
   },
   "exports": {
-    "import": "./lib/esm/nylas.js",
-    "require": "./lib/cjs/nylas.js",
-    "types": "./lib/types/nylas.d.ts"
+    "import": {
+      "types": "./lib/types/nylas.d.ts",
+      "default": "./lib/esm/nylas.js"
+    },
+    "require": {
+      "types": "./cjs-wrapper.d.ts",
+      "default": "./cjs-wrapper.js"
+    }
   }
 }

src/nylas.ts

@@ -24,7 +24,7 @@ import { Notetakers } from './resources/notetakers.js';
  * A Nylas instance holds a configured http client pointing to a base URL and is intended to be reused and shared
  * across threads and time.
  */
-export default class Nylas {
+class Nylas {
   /**
    * Access the Applications API
    */
@@ -122,3 +122,5 @@ export default class Nylas {
     return this;
   }
 }
+
+export default Nylas;

tsconfig.cjs.json

@@ -3,5 +3,8 @@
   "compilerOptions": {
     "module": "commonjs",
     "outDir": "lib/cjs",
+    "esModuleInterop": true,
+    "allowSyntheticDefaultImports": true,
+    "moduleResolution": "node"
   },
 }

tsconfig.json

@@ -3,7 +3,7 @@
     "target": "es2021",
     "declaration": true,
     "declarationDir": "lib/types",
-    "esModuleInterop": false,
+    "esModuleInterop": true,
     "allowSyntheticDefaultImports": true,
     "resolveJsonModule": true,
     "moduleResolution": "node",