I am creating an application in Angular 12 and the latest NgRx library for turorial purposes. I have the below model, action, reducer, and app state class.
Model
export interface Tutorial {
name: string;
url: string;
}
Actions
import { Injectable } from '@angular/core'
import { Action } from '@ngrx/store'
import { Tutorial } from '../_models/tutorial.model'
export const ADD_TUTORIAL = '[TUTORIAL] Add'
export const REMOVE_TUTORIAL = '[TUTORIAL] Remove'
export class AddTutorial implements Action {
readonly type = ADD_TUTORIAL
constructor(public payload: Tutorial) {}
}
export class RemoveTutorial implements Action {
readonly type = REMOVE_TUTORIAL
constructor(public payload: number) {}
}
export type Actions = AddTutorial | RemoveTutorial
Reducer
import { Action } from '@ngrx/store'
import { Tutorial } from '../_models/tutorial.model';
import * as TutorialActions from './../_actions/tutorial.actions'
const initialState: Tutorial = {
name: 'Initial Tutorial',
url: 'http://google.com'
}
export function reducer(state: Tutorial[] = [initialState], action: TutorialActions.Actions) {
switch(action.type) {
case TutorialActions.ADD_TUTORIAL:
return [...state, action.payload];
default:
return state;
}
}
App State
import { Tutorial } from "./_models/tutorial.model";
export interface AppState {
readonly tutorial: Tutorial[];
}
Now I would like to import the reducer in the app.module.ts file. Here is the code:
import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';
import { StoreModule } from '@ngrx/store';
import { reducer } from './_reducers/tutorial.reducer';
import { ReadComponent } from './read/read.component';
import { CreateComponent } from './create/create.component';
@NgModule({
declarations: [
AppComponent,
ReadComponent,
CreateComponent
],
imports: [
BrowserModule,
StoreModule.forRoot({ tutorial: reducer }),
AppRoutingModule,
],
providers: [],
bootstrap: [
AppComponent
]
})
export class AppModule { }
But in the app.module.ts file, importing reducer is causing an error. The error is shown below:
Error: src/app/app.module.ts:19:29 - error TS2322: Type '(state: Tutorial[] | undefined, action: Actions) => Tutorial[]' is not assignable to type 'ActionReducer<Tutorial[], Action>'. Types of parameters 'action' and 'action' are incompatible. Type 'Action' is not assignable to type 'Actions'. Property 'payload' is missing in type 'Action' but required in type 'RemoveTutorial'.
19 StoreModule.forRoot({ tutorial: reducer }), ~~~~~~~~
src/app/_actions/tutorial.actions.ts:20:17 20 constructor(public payload: number) {} ~~~~~~~~~~~~~~~~~~~~~~ 'payload' is declared here.
As I am new in NgRx, I don't understand why the problem is happening. Please help me to solve the problem.
It's been a while since I used that syntax it it might be a regression bug. You can assert it to an ActionReducerMap
StoreModule.forRoot({ tutorial: reducer } as ActionReducerMap<any,any>)
Also, I would suggest to take a look at the createAction and createReducer syntax - it makes things simpler.