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Redux Lite for local states
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/* | |
* Minimal redux for local states | |
* @link https://spin.atomicobject.com/2017/07/24/redux-action-pattern-typescript/ | |
*/ | |
export interface ReducerFn<S, A> { | |
(state: S, action: A): S | |
} | |
export interface Action<T> { | |
readonly type: any; | |
payload?: T; | |
} | |
export class StoreLite<S, A> { | |
private subject: Subject<S>; | |
constructor ( | |
initialState: S, | |
private reducerFn: ReducerFn<S, A> | |
) { | |
this.subject = new BehaviorSubject(initialState); | |
} | |
public dispatch(action: A): void { | |
// TODO ... typed immutable record here ... initial state is there, S is there ... oculd be possible | |
this.subject.next(this.reducerFn(this.state, action)); | |
} | |
public subscribe(/* ... */): Subscription { | |
return this.subject.asObservable().subscribe(/* ... */); | |
} | |
} | |
// --- user land | |
interface MyState { | |
count: number; | |
} | |
export const initialState: MyState = { | |
count: 100 | |
}; | |
export class FooAction implements Action<number> { | |
readonly type = "FOO"; | |
constructor( | |
public payload: number | |
) {} | |
} | |
type ActionTypes = FooAction; | |
export const reducer: ReducerFn<MyState, ActionTypes> = | |
(state = initialState, action) => { | |
switch (action.type) { | |
case "FOO": | |
return { count: action.payload }; | |
} | |
return state; | |
} | |
const localRedux: StoreLite<MyState, ActionTypes> = new StoreLite( | |
initialState, | |
reducer | |
); | |
localRedux.dispatch(new FooAction(123)); |
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