CODEWITHSUNDEEP
node.jstypescriptasynchronousnestjs
jashinhidan
jashinhidan

Reputation: 71

NestJS call async service on init

in my nestjs app I have a service which use a factory service to initialize some kind of adapter. Since all the methods in my service need to use the adapter initialized by the factory service, I was wondering if there is a way to call the factory service just once. I cannot do it in the constructor because it is an asynchronous call.

What's the best way to achieve it?

This is my service:

@Injectable()
export class MyService {
    constructor(
        private readonly factoryService: FactoryService
    ) {}

and this is the call that I need to do:

await this.factoryService.createAdapter(adapter);

Upvotes: 3

Views: 4841

Answers (1)

Sankalp Mukim
Sankalp Mukim

Reputation: 80

Looks like if you initialize this service (or a sub service) asynchronously, you'll be able to handle your factory. I was facing a similar situation when I found in the Nest JS documentation asynchronous providers.

https://docs.nestjs.com/fundamentals/async-providers

It felt like an inelegant solution (and too much work to divide the initialization into another sub service...) so at least for the time I used a variable to check the state but at some point later, I'll use the documented approach.

Example of a simple workaround

If you choose to use the documentation based example, I found their TypeORM recipe as a nice example of how to set it up properly.

https://docs.nestjs.com/recipes/sql-typeorm

Hope this helps. Please comment any feedback!

Upvotes: 2

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