MikroORM vs TypeORM: What are the differences?

MikroORM and TypeORM are both TypeScript-based Object-Relational Mapping (ORM) libraries for simplifying database interactions in Node.js applications. Let's explore the key differences between them:

1. ORM Support for Multiple Databases: MikroORM provides support for various databases like PostgreSQL, MySQL, MongoDB, and SQLite, whereas TypeORM supports a wider range of databases, including not only the ones supported by MikroORM but also Oracle, Microsoft SQL Server, and others.

2. Nested Transactions: MikroORM offers nested transactions, allowing the developer to manage multiple levels of transactions within one another, which can be useful in complex scenarios. On the other hand, TypeORM does not explicitly support nested transactions, although it provides alternatives like savepoints and transaction isolation levels.

3. Code Organization and Simplicity: MikroORM follows a minimalistic and opinionated approach to code organization, providing fewer code choices to developers and promoting simplicity. In contrast, TypeORM offers more flexibility and customization options, allowing developers to implement their preferred coding patterns and structures when working with the ORM.

4. Integration with Unique Database Features: MikroORM is designed to seamlessly integrate with unique database features like entity id mappers, serialization, validation, and filtering. TypeORM, however, does not focus explicitly on these database features, leaving their implementation and integration as additional tasks for the developers.

5. Query Building Approaches: MikroORM takes a Query Builder approach to build complex queries, which can be more intuitive and easier to use when compared to raw SQL queries. TypeORM, on the other hand, supports both Query Builder and Repository patterns, allowing developers to choose the most suitable approach for their specific needs.

6. Package Size: MikroORM has a smaller package size, making it lightweight and suitable for projects with limited disk space or bandwidth. TypeORM, in contrast, has a larger package size due to its broader range of functionalities and wider database support.

In summary, MikroORM and TypeORM are TypeScript-friendly ORMs, with MikroORM emphasizing simplicity and extensibility, while TypeORM provides a comprehensive solution with broad database support and advanced features.