nestjs-cls-neverthrow

A @TransactionalResult decorator for @nestjs-cls/transactional that works with neverthrow's ResultAsync. When the decorated method returns an Err, the transaction automatically rolls back.

For methods that don't use neverthrow, use the original @Transactional from @nestjs-cls/transactional.

Installation

npm install nestjs-cls-neverthrow

Usage

import { Transactional } from '@nestjs-cls/transactional';        // plain returns
import { TransactionalResult } from 'nestjs-cls-neverthrow';      // ResultAsync returns

@TransactionalResult — for ResultAsync returns

@Injectable()
export class UserService {
  constructor(
    private readonly txHost: TransactionHost<TransactionalAdapterTypeOrm>,
  ) {}

  @TransactionalResult()
  createUser(name: string): ResultAsync<User, Error> {
    const repo = this.txHost.tx.getRepository(User);
    return ResultAsync.fromSafePromise(repo.save({ name }));
    // Ok → transaction commits
  }

  @TransactionalResult()
  failingMethod(): ResultAsync<void, Error> {
    const repo = this.txHost.tx.getRepository(User);
    return ResultAsync.fromSafePromise(repo.save({ name: 'will be rolled back' }))
      .andThen(() => errAsync(new Error('oops')));
    // Err → transaction rolls back
  }
}

@Transactional — for plain returns

For methods that don't return ResultAsync, use the original decorator from @nestjs-cls/transactional:

import { Transactional } from '@nestjs-cls/transactional';

@Injectable()
export class PlainService {
  constructor(
    private readonly txHost: TransactionHost<TransactionalAdapterTypeOrm>,
  ) {}

  @Transactional()
  async createUser(name: string): Promise<User> {
    const repo = this.txHost.tx.getRepository(User);
    return repo.save({ name });
  }
}

Behavior

| Return Value | Transaction | | --- | --- | | okAsync(value) / ok(value) via ResultAsync | Commits | | errAsync(error) / err(error) via ResultAsync | Rolls back, returns Err to caller |

Peer Dependencies

• @nestjs-cls/transactional >=3.0.0
• neverthrow >=6.0.0