fix: ESM compatibility fixes and improved error handling

Author: nadeem-cs

.talismanrc

@@ -3,7 +3,7 @@ fileignoreconfig:
   ignore_detectors:
     - filecontent
 - filename: package-lock.json
-  checksum: af3bffd9f46b71daf5b8dd0b3eace75dfd367e359b11503259dc00a8c7105bf0
+  checksum: 59653dc17458f6bddffb6178bfb8f8191ad4715f41a788082a11d3b08e966b4c
 - filename: .husky/pre-commit
   checksum: 5baabd7d2c391648163f9371f0e5e9484f8fb90fa2284cfc378732ec3192c193
 - filename: test/request.spec.ts
@@ -14,4 +14,6 @@ fileignoreconfig:
   checksum: 08ccd6342b3adbeb7b85309a034b4df4b2ad905a0cc2a3778ab483b61ba41b9e
 - filename: test/retryPolicy/delivery-sdk-handlers.spec.ts
   checksum: 6d22d7482aa6dccba5554ae497e5b0c3572357a5cead6f4822ee4428edc12207
+- filename: test/contentstack-core.spec.ts
+  checksum: 2d1e0f63ad8ea37890de2aa6c7e394c83488888f4a40ad7a71eeba2290b95924
 version: ""

CHANGELOG.md

@@ -1,5 +1,14 @@
 ## Change log
 
+### Version: 1.3.8
+#### Date: Jan-15-2026
+ - Fix: Add .js extensions to relative imports in ESM build for proper module resolution
+ - Fix: Change lodash import from named import to default import for ESM compatibility with CommonJS modules
+
+### Version: 1.3.7
+#### Date: Jan-12-2026
+ - Fix: Improve error messages
+
 ### Version: 1.3.6
 #### Date: Jan-05-2026
  - Fix: Resolve qa dependency snyk issue

README.md

@@ -1,46 +1,129 @@
+# @contentstack/core
+
 [![Contentstack](https://www.contentstack.com/docs/static/images/contentstack.png)](https://www.contentstack.com/)
-## TypeScript Core SDK for Contentstack
+
+TypeScript Core SDK for Contentstack - A foundational library providing core modules and utilities for Contentstack TypeScript SDKs.
+
+## About Contentstack
 
 Contentstack is a headless CMS with an API-first approach. It is a CMS that developers can use to build powerful cross-platform applications in their favorite languages. Build your application frontend, and Contentstack will take care of the rest. [Read More](https://www.contentstack.com/).
 
-### Prerequisite
+## Description
 
-You need Node.js version 4.4.7 or later installed to use the Contentstack TS Core SDK.
+This package contains core modules and utilities used by the [Contentstack TypeScript Delivery SDK](https://github.com/contentstack/contentstack-javascript/). It provides essential functionality including HTTP client configuration, error handling, request management, parameter serialization, and retry policies.
 
-## Installation
+## Features
 
-```
+- **HTTP Client**: Configurable Axios-based HTTP client with support for custom adapters
+- **Error Handling**: Comprehensive error classes for API and Contentstack-specific errors
+- **Request Management**: Request handling with interceptors and custom error callbacks
+- **Parameter Serialization**: Custom parameter serialization for API requests
+- **Retry Policies**: Built-in retry logic for handling rate limits and transient errors
+- **TypeScript Support**: Full TypeScript definitions included
+- **Multiple Build Formats**: Supports CommonJS, ESM, UMD, and TypeScript declarations
+
+## Important Note
+
+**This package is an internal dependency** used by Contentstack TypeScript SDKs. End users should **not** install this package directly. Instead, install the appropriate Contentstack SDK (e.g., [Contentstack TypeScript Delivery SDK](https://github.com/contentstack/contentstack-typescript/)), which will automatically include this package as a dependency.
+
+## For SDK Developers
+
+If you are developing or maintaining a Contentstack SDK and need to use this core package directly, you can install it as a dependency:
+
+```bash
 npm install @contentstack/core
 ```
 
-## Use case
+Then import the modules:
 
-This package contains some core modules and utilities used by the [Contentstack Typescript Delivery SDK](https://github.com/contentstack/contentstack-javascript/) SDK.
+```typescript
+import {
+  httpClient,
+  ContentstackError,
+  ApiError,
+  // ... other exports
+} from '@contentstack/core';
+```
 
 ## Development
 
-### Create the build:
+### Prerequisites
 
+- Node.js version 4.4.7 or later
+
+### Setup
+
+Clone the repository and install dependencies:
+
+```bash
+git clone https://github.com/contentstack/contentstack-js-core.git
+cd contentstack-js-core
+npm install
 ```
+
+### Build
+
+Build all output formats (CommonJS, ESM, UMD, and TypeScript declarations):
+
+```bash
 npm run build
 ```
 
-### Run Scripts:
-
-Run the unit tests:
+Build specific formats:
 
+```bash
+npm run build:cjs    # CommonJS
+npm run build:esm    # ES Modules
+npm run build:umd    # UMD
+npm run build:types  # TypeScript declarations
 ```
+
+### Testing
+
+Run unit tests:
+
+```bash
 npm run test
 ```
 
-Run the lint tests:
+Run linting:
 
-```
+```bash
 npm run lint
 ```
 
-Pack the SDK:
+### Packaging
 
-```
+Create a package tarball:
+
+```bash
 npm run package
-```
+```
+
+### Clean
+
+Clean build artifacts:
+
+```bash
+npm run clean
+```
+
+## License
+
+This project is licensed under the MIT License. See the [LICENSE.txt](LICENSE.txt) file for details.
+
+## Repository
+
+- **GitHub**: [contentstack/contentstack-js-core](https://github.com/contentstack/contentstack-js-core)
+
+## Related Projects
+
+- [Contentstack TypeScript Delivery SDK](https://github.com/contentstack/contentstack-javascript/)
+
+## Support
+
+For issues and feature requests, please visit the [GitHub Issues](https://github.com/contentstack/contentstack-js-core/issues) page.
+
+---
+
+Copyright (c) 2016-2025 Contentstack. All rights reserved.