Mongoose-Legacy

The Mongoose-Legacy library was created to address the challenge of migrating a large codebase that heavily relies on callback syntax to the latest version of Mongoose, which uses promises. Rewriting thousands of instances of callback syntax into promises can be a daunting task in a large project, making it impractical to update to the latest version of Mongoose without significant code changes.

To overcome this limitation, Mongoose-Legacy provides an updated instance of Mongoose (v7) that retains compatibility with callbacks and other deprecated methods. This allows existing projects to benefit from the advantages of the latest version of Mongoose, such as improved performance, new features, and bug fixes, without the need for extensive code modifications.

Installation

To use this library, import it instead of the regular Mongoose module wherever you have defined your model. Install it using npm:

npm install mongoose-legacy

By importing the mongoose-legacy library, you can seamlessly integrate the latest version of Mongoose into your project, leveraging its benefits without breaking existing code that relies on callback syntax.

Usage

In your code, require the library and use it to define your Mongoose models:

var { mongoose, Schema } = require('mongoose-legacy');

var userSchema = new Schema({
  // Define your schema fields here
});

var User = mongoose.model('User', userSchema);

// Make this available in our Node applications
module.exports = User;

Examples

Here are some examples demonstrating the usage of the Mongoose-Legacy library:

Example 1: Using Model.findById with Callback and Async/Await

Callback:

User.findById(userId, function (err, user) {
  if (err) {
    console.error(err);
    return;
  }
  console.log(user);
});

Async/Await:

try {
  const user = await User.findById(userId);
  console.log(user);
} catch (err) {
  console.error(err);
}

Example 2: Query Chaining with Exec and Callbacks, and using Async/Await

Callback:

User.find()
  .where('age').gte(18)
  .exec(function (err, users) {
    if (err) {
      console.error(err);
      return;
    }
    console.log(users);
  });

Async/Await:

try {
  const users = await User.find().where('age').gte(18).exec();
  console.log(users);
} catch (err) {
  console.error(err);
}

Example 3: Using Update Query (deprecated in v7) with Mongoose-Legacy

User.update(
  { name: 'John' },
  { $set: { age: 30 } },
  function (err, result) {
    if (err) {
      console.error(err);
      return;
    }
    console.log(result);
  }
);

The Mongoose-Legacy library adds support for the deprecated update query by internally using updateOne. This ensures that you can continue using the familiar update method in your code without any compatibility issues.

Documentation

For detailed documentation on how to use Mongoose and its features, refer to the official Mongoose documentation.

Compatibility

Mongoose-Legacy is backward compatible up to Mongoose version 4 and is designed to work with the latest Mongoose version (v7). It provides a seamless transition to the new version, allowing you to maintain existing code while benefiting from the latest enhancements and features.

License

This library is released under the ISC License. Please see the LICENSE file for more details.

Author

This library is developed and maintained by Trailingcrypto. Feel free to reach out with any questions or feedback.

Acknowledgements

We would like to thank the Mongoose team for their great work on the original Mongoose library, which serves as the foundation for Mongoose-Legacy. Your contributions and efforts are invaluable to the development community.