nestjs-hybrid-create-example

This is a NestJS example demonstrating an uncommon use case of injecting additional custom dependencies into a transient class instance, useful if you want to augment transient class instances with additional data that is visible in the constructor, supplied at runtime dynamically by the creator, so it's a hybrid between using "new" directly and using the container. Normally you would have to supply the additional data after creation from the container.

This can reduce some boilerplate in some cases, but the approach is far from clean, given that it is copying internal Reflect metadata, and possibly not supporting all injection cases. It's certainly not a well-supported operation and could break in the future. This is merely an interesting exercise of working with the NestJS DI system, and not recommended for real code.

Basic usage

See create-with-supplied.ts. The SuppliedDepProvider needs to be registered.

Decorate parameters that are to be supplied manually:

constructor(
   private readonly otherService: OtherService, // Injected from container
   @Supplied("secret") private readonly secret: string, // Injected from supplied arg
) {}

Assign the supplied parameters during creation:

const instance = createWithSupplied(moduleRef, MyClass, {
   secret: "my secret value",
});

See hybrid-create-example.spec.ts for a minimal test case.