redux-observable-decorator

Decorators for Redux Observable

When using Redux with Angular with angular-redux/store and redux-observable, it's common to create your epics as an injectable class, and when configuring the store - creating an epic middleware for each one, or using combineEpics:

@Injectable()
export class SomeEpics {
	epicOne = (action$) => action$.ofType('PING').pipe(mapTo({type: 'PONG'}));
	epicTwo = (action$) => action$.ofType('ACTION_IN').pipe(mapTo({type: 'ACTION_OUT'}));
}

@NgModule({

})
export class AppModule {
	constructor(ngRedux: NgRedux, someEpics: SomeEpics) {
		let epics = combineEpics(
			someEpics.epicOne,
			someEpics.epicTwo
		);
		let epicMiddleware = createEpicMidleware();

		ngRedux.configureStore(reducer,[epicMiddleware]);
		epicMiddleware.run(epics);

		// or

		let epicOne = createMiddleware(someEpics.epicOne);
		let epicTwo = createMiddleware(someEpics.epicTwo);

		ngRedux.configureStore(reducer,[epicOne, epicTwo]);
	}
}

This decorator is intended to make it easier to mark which properties / methods in a class are Epics to simplify creating the epic middleware for your application.

import { Epic } from 'redux-observable-decorator';

@Injectable()
export class SomeEpics {
	@Epic() epicOne = (action$) => action$.ofType('PING').pipe(mapTo({type: 'PONG'}));
	@Epic() epicTwo = (action$) => action$.ofType('ACTION_IN').pipe(mapTo({type: 'ACTION_OUT'}));
}

import { combineDecoratedEpics } from 'redux-observable-decorator';
import { createEpicMiddleware } from 'redux-observable';

@NgModule({

})
export class AppModule {
	constructor(ngRedux:NgRedux, someEpics:SomeEpics) {
		let epics = combineDecoratedEpics(someEpics);
		const epicMiddleware = createEpicMiddleware();

		ngRedux.configureStore(reducer,[epicMiddleware]);
		epicMiddleware.run(epics);
	}
}

This can be used with vanilla redux also - as seen in the unit tests...

class Test {
	@Epic() epic = (action$) => action$.ofType('TEST_IN').pipe(mapTo({ type: 'TEST_OUT' }));
}

const reducer = (state = [], action) => state.concat(action);
const epics = new Test();
const epicMiddleware = createEpicMiddleware(epics);
const store = createStore(reducer, applyMiddleware(epicMiddleware));
epicMiddleware.run(combineDecoratedEpics(epics));

Inspiration

The @Effect decorator from ngrx/effects

Todo

• [ ] Better docs
• [ ] Publish on NPM
• [ ] Improve tests
• [ ] Get test coverage working
• [ ] Some Anglar 2 / integration tests
• [ ] Example App
• [ ] Strategy for lazy loading epics (to support code-splitting)?