`@n8n/di` is a dependency injection (DI) container library, based on [`typedi`](https://github.com/typestack/typedi).
npm install @n8n/di@n8n/di is a dependency injection (DI) container library, based on typedi.
n8n no longer uses typedi because:
- typedi is no longer officially maintained
- Need for future-proofing, e.g. stage-3 decorators
- Small enough that it is worth the maintenance burden
- Easier to customize, e.g. to simplify unit tests
``typescript
// from https://github.com/typestack/typedi/blob/develop/README.md
import { Container, Service } from 'typedi';
@Service()
class ExampleInjectedService {
printMessage() {
console.log('I am alive!');
}
}
@Service()
class ExampleService {
constructor(
// because we annotated ExampleInjectedService with the @Service()
// decorator TypeDI will automatically inject an instance of
// ExampleInjectedService here when the ExampleService class is requested
// from TypeDI.
public injectedService: ExampleInjectedService
) {}
}
const serviceInstance = Container.get(ExampleService);
// we request an instance of ExampleService from TypeDI
serviceInstance.injectedService.printMessage();
// logs "I am alive!" to the console
`
Requires enabling these flags in tsconfig.json:
`json``
{
"compilerOptions": {
"experimentalDecorators": true,
"emitDecoratorMetadata": true
}
}