How to migrate a PUT endpoint to a command based app (event sourcing)

Question

I'm almost done with implementing event sourcing using CQRS module of NestJS, but now there is something I don't know how to handle. Currently, I have cron jobs that send transactions hourly to a my PUT /transactions endpoint. The payload is like this:

{
    "status": "pending",
    "amount": 10000,
    "uid": "test123",
    "transaction_id": "test-transaction1234",
}

When the transaction is sent to the endpoint, I don't know which fields have changed yet. I have four posible commands: CreateTransactionCommand, UpdateAmountCommand, ApproveTransactionCommand, DeclineTransactionCommand. Two commands could occur at 'the same time', for example and UpdateAdmount and then an ApproveTransaction. The first one should aways occur at first.

How should I handle that? I was thinking about something like this, is it a good solution?

  @Put()
  async createOrUpdate(@Body() dto: Transaction) {
    try {
      await this.transactionsService.createTransaction(dto);
    } catch (e) {
      if (typeof e == ExistingTransactionError) console.error(e);
      else throw e;
    }
    try {
      await this.transactionsService.updateTransactionAmount(dto);
    } catch (e) {}
    if (dto.status === 'approved')
      await this.transactionsService.approveTransaction(dto);
    if (dto.status === 'declined')
      await this.transactionsService.declineTransaction(dto);
  }

Answer 1

Okay, I simply did a PUT endpoint, and thanks to the power of the aggregate root, it's pretty easy to know which command I can do.

  @Put()
  async createOrUpdate(@Body() dto: TransactionEventDto) {
    try {
      return await this.transactionsService.createTransaction({
        ...dto.payload,
        status: 'pending',
      });
    } catch (e) {
      if (!(e instanceof TransactionAlreadyCreatedError))
        throw new HttpException(e.message, HttpStatus.BAD_REQUEST, e);
    }
    try {
      const { transaction_id, amount, status } = dto.payload;
      await this.transactionsService.updateTransactionAmount(
        transaction_id,
        amount,
      );
      if (status === 'approved') {
        return await this.transactionsService.approveTransaction(
          transaction_id,
        );
      }
      if (status === 'declined') {
        return await this.transactionsService.declineTransaction(
          transaction_id,
        );
      }
      return;
    } catch (e) {
      throw new HttpException(e.message, HttpStatus.BAD_REQUEST, e);
    }
  }

If the order matter, just use the 'sequential way' of promise (i.e await in chain)