reactivex-redux

RxRedux

Inspired by ReactorKit

RxRedux is a framework for React Web Application to seperate view model from view to make entire codes more testable using Rxjs.

Most of concepts of this project are identical to ReactorKit, You can check the detailed explanation of specific concepts of this framework in its repository.

Installation

npm i reactivex-redux

Reactor (a.k.a. Store)

Reactor is "UI-independent" View-Model layer which manages the state of a view.

Main Concepts

• Action : Abstraction of the user interaction.
• Mutation : The stage which can mutate the app's state.
• State : Abstraction of view's state.

View -> Dispatching Action -> [Action -> Mutation -> State] -> new state -> View Update.

How Reactor works with React-Components.

1. An element in the component (like a button) dispatches the action.
2. Reactor's Action receives the action.
3. Reactor convert this stream to Mutation stream through mutate() method.
4. Reactor's Mutation stage mutates the states (side effecct happens in this step).
5. This will call reduce() methods to reduce old state to new state.
6. new states will be updated in the view component whcih subscribes the Reactor.

Example: Reactor

Reactor is an abstract class, which requires you to implement mutate() and reduce() with Action, Mutation, State types.

Example 1: Creating Type for Action, Mutation, State

Action

export const CLICKTOPIC = "CLICKTOPIC"

export interface CLICKTOPIC {
    type: typeof CLICKTOPIC;
    newTopic: Topic,
}

export type ForumAction = CLICKTOPIC

Mutation

export const SETLOADING = "SETLOADING"
export const FETCHLIST = "FETCHLIST"

export interface SETLOADING {
    type: typeof SETLOADING,
    isLoading: boolean,
}

export interface FETCHLIST {
    type: typeof FETCHLIST,
    list: ListType[],
    page: number
}

type ForumMutation = SETLOADING | FETCHLIST 

State & InitialState

export interface ForumState {
    topic : Topic,
    mode: Mode,
    page: number,
    list: ListType[],
    isLoading:boolean,
    isError:boolean,
    post?: ContentType,
    isLogined: boolean,
}
export const ForumStateInitialState : ForumState = {
    isError: false,
    isLoading: true,
    page: 1,
    mode:"list",
    topic:"tips",
    post: undefined,
    list:[],
    isLogined: false,
}

If you know a better way for typing, go for it. you could check out Redux's action generator library. typesface-actions

Construct Class

You need to implement two method mutate() and reduce().

class ForumReactor extends Reactor<ForumAction, ForumState, ForumMutation> {

   mutate(action: ForumAction): Observable<ForumMutation> {
	... // convert action stream to mutation stream. 
   }
   reduce(state: ForumState, mutation: ForumMutation) {
        ... // reduce old state to new state.
   }
} 

example of mutate() and reduce()

Using Rxjs's concat() methods, you can serialize your stream.

mutate(...){
....
case "CLICKPAGE":
    return concat(
	// 1. loading on
	of<ForumMutation>({type:"SETLOADING", isLoading: true}),
	// 2. fetching List
	this.fetchList(this.currentState.topic, action.newPage).pipe(
	    takeUntil(this.action.pipe(filter(value => value === action))),
	    map<ListType[], ForumMutation>( res => {
		return {type:"FETCHLIST", list: res, page: 1 } 
	    })
	),
	// 3. Loading off
	of<ForumMutation>({type:"SETLOADING", isLoading: false}),
    }
   ...

reduce(...) {
...
    case "FETCHLIST":
	newState.isLoading = false;
	if (mutation.list.length === 0){
	    newState.isError = true;
	    return newState
	} else {
	    newState.list = mutation.list;
	    newState.page = mutation.page;
	    return newState
	}
 ....
}

Usage

const reactor = new ForumReactor(initialState)
...
//dispatching action.
reactor.dispatch({type:"CLICKPAGE"})

//subscribe reaction from Reactor
reactor.state.subscribe( res => console.log(res) )

Methods

Constructor

parameter	required	default
initialState	true	none
isStubEnabled	false	false

mutate() and reduce()

mutate() receives a dispatched action, and generates an Observable<Mutation>

reduce() reduces old states with Mutation to new states.

See above for detailed examples.

transform()

Before your stream is delivered to one of the stage, you can transform your observable stream.

In this example, messages are logged before your states updated. (i.e. before your stream get to the State stage)

transformState(state: Observable<State>): Observable<State> {
	return state.pipe( tap( _ => console.log("state update!"))
}

View-Binding

RxRedux provides a way to bind your Reactor with React-Component.

withReactor(component)

As of 1.0.4, RxRedux provides higher order component called withReactor()

parameter	required	default
Component	true	none
parentFilterMapper	false	false
transfromStateStreamFromThisComponent	false	true
skipSync	false	true

This HOC automatically subscribes reactor's from parents component.

• parentFilterMapper : You don't have to subscribe all of the properties in state object. you can specify keys you want to subscribe as a mapper function.
• transfromStateStreamFromThisComponent : If this is true, the mapper function will automatically be applied to child component which is wrapped by withReactor()
• skipSync : A reactor emits a current state when you start subscribing (i.e. when withReactor(Component) is mounted). You can ignore this call to avoid redundant re-rendering.

(Auomatic) Testing

Testing for Reactor.

You can easily testing Reactor since it is UI-Independent.

for example,

1. Action testing

it('click write -> mode change test ', done  => {
	
	// create reactor
	reactor = new  ForumReactor(initialState);
	
	// dispatch action.
	reactor.dispatch({type:"CLICKWRITE"})
	
	// check its state.
	expect(reactor.currentState.mode).toBe("edit")
	done();
})

2. Testing containing side effect (API Call)

it('5. side effect : click topic -> topic change -> loading -> (success) -> loading -> isError false test', done  => {

	// API Request Mock-up.
	moxios.wait(() => {
		const  request = moxios.requests.mostRecent()
		request.respondWith({ status:  200, response:  listResultMockup }) 
	})

	// create reactor
	reactor = new  ForumReactor(initialState);


	let  state_change = 0;

	//subscribe reactor to check we received expected value.
	from(reactor.state).subscribe(
		
		state  => {
		if(state_change === 1) {
		    expect(state.topic).toBe("tips");
		} else  if (state_change === 2) {
		    expect(state.isLoading).toBeTruthy();
		} else  if (state_change === 3) {
		    expect(state.list.length).toBe(2);
		} else  if (state_change === 4) {
		    expect(state.isLoading).toBeFalsy();
		    expect(state.isError).toBeFalsy();
		    done();
		} else {
		    done.fail();
		}
		    state_change++;
		}
	    )
	    reactor.action.next({type:"CLICKTOPIC", newTopic:  "tips"})
	})

Testing for Component<->Reactor.

Component<->Reactor testing can be tested with Stub

What is Stub?

Stub is a testing utility implemented in Reactor. Stub can log every actions you've dispatched from Component, and it can force state changes.

To enable Stub, you need to set isStubEnbabled as true in constuctor arguments.

const reactor = new ForumReactor(initialState, true)

Example

it('9. View Binding Check', done  => {
	
	// create Reactor with StubEnableMode on.
	reactor = new  ForumReactor(initialState, true);

	// mount by `Enzyme`
	const  wrapper = shallow(<R6Table></R6Table>);

	// check reactor exist to bind with in original code.
	expect((wrapper.instance() as  any).reactor).not.toBe(undefined);

	// inject new reactor in the code.
	(wrapper.instance() as  any).reactor = reactor;

	// you can remount your component or call custom bind() function in your component.
	(wrapper.instance() as  any).bind(reactor);

	// simulate button action using `enzyme` testing.
	wrapper.find('button').at(0).simulate('click')

	// stub can log every actions from view components.
	expect(reactor.stub.lastAction.type).toBe("CLICKBACK");

	// stub also can force new state.
	reactor.stub.state.next({...initialState, mode :  "edit"});

	// you can check new state in Component.
	expect((wrapper.state() as  ForumState).mode).toBe("edit");
	
	done();
})

Additional Tips.

Scheuder

You can specify RxJs's scheduler when you defining Reactor class, but it must be a serial queue.

ReactorHook (experimental)

RxRedux supports functional components using custom hooks, but you need to define new class which extends ReactorHook<Action,State,Mutation>

ReactorHook is same as Reactor class, but it has depedency on react library's native hook methods.

const [reactor, currentState] = SomeHookReactor.use(initialState)

This will also update your functional view component every time current state changes.

RxjsExtension

This provides some Rxjs operator extension. catchErrorJustReturn() & catchErrorReturnEmpty& deepDistinctUntilChanged()

ReactorGroup

This injects Reactor its child.

<ReactorGroup reactor={this.reactor}>
	<R6CommunityNavigation></R6CommunityNavigation>
	<R6List></R6List>
	<R6ListFooter></R6ListFooter>
	<R6PostWrite></R6PostWrite>
	<R6Post></R6Post>
</ReactorGroup>

To-do list

• [x] initial Commit
• [X] 비동기 대응.
• [X] 비동기 처리 에러.
• [X] 프로젝트 테스트 코드 추가 및 테스트.
• [X] 테스트 기능.
• [X] 문서작성.
• [X] 뷰 .
• [X] 훅기능 추가 (beta)
• [ ] 코드 테스트.
• [ ] 디버깅 기능 추가.

Dependency

• Rxjs
• lodash
• react

업데이트 내역

• 1.0.4 : withReactor update.
• 1.0.4 : bug-fix : state is undeliberately mutated.
• Readme update.
• 글로벌 스토어 삭제, HOC 바인딩 방식, ReactorGroup & Rxjsextension추가.