nestjs / TypeOrm database transaction

Question

Assuming we have 2 services, A and B. Service A has a function doing the following:

1. Validate the data
2. Call a service B function, that makes changes to

Answer 1

In this case, you have to use the same transaction manager for both database operations. Unfortunately, I do not have an example repository, but I have found a potential solution using Continuation Local Storage (CLS) in Node:

https://github.com/typeorm/typeorm/issues/1895

This applies to Express.js, but you can create an instance of TransactionManager (for example, in a nest middleware) and store it per each request context. You then will be able to re-use this transactional manager across your service method calls, provided they are annotated with the @Transaction decorator implementation in the link above.

If there are no errors in your function chain, the transaction manager will commit all the changes made. Otherwise, the manager will roll back any changes.

Hope this helps!