@ngrx/store

What is @ngrx/store?

@ngrx/store is a state management library for Angular applications, inspired by Redux. It provides a way to manage state in a predictable manner using actions, reducers, and selectors.

What are @ngrx/store's main functionalities?

State Management

This code demonstrates how to set up a basic state management system using @ngrx/store. The StoreModule is imported and configured with a reducer.

import { StoreModule } from '@ngrx/store';
import { counterReducer } from './counter.reducer';

@NgModule({
  imports: [
    StoreModule.forRoot({ count: counterReducer })
  ]
})
export class AppModule {}

Actions

This code shows how to create actions using the createAction function. Actions are dispatched to trigger state changes.

import { createAction } from '@ngrx/store';

export const increment = createAction('[Counter] Increment');
export const decrement = createAction('[Counter] Decrement');
export const reset = createAction('[Counter] Reset');

Reducers

This code defines a reducer function using createReducer and on functions. The reducer handles different actions to update the state.

import { createReducer, on } from '@ngrx/store';
import { increment, decrement, reset } from './counter.actions';

export const initialState = 0;

const _counterReducer = createReducer(initialState,
  on(increment, state => state + 1),
  on(decrement, state => state - 1),
  on(reset, state => initialState)
);

export function counterReducer(state, action) {
  return _counterReducer(state, action);
}

Selectors

This code demonstrates how to create selectors to read specific pieces of state. Selectors are used to derive data from the store.

import { createSelector, createFeatureSelector } from '@ngrx/store';

export const selectCounterState = createFeatureSelector<number>('count');

export const selectCount = createSelector(
  selectCounterState,
  (state: number) => state
);

Other packages similar to @ngrx/store

redux

Redux is a popular state management library for JavaScript applications. It is similar to @ngrx/store in that it uses actions, reducers, and a single store to manage state. However, Redux is framework-agnostic and can be used with any JavaScript framework or library.

mobx

MobX is a state management library that uses observables to manage state. Unlike @ngrx/store, which follows a more rigid, predictable state management pattern, MobX allows for more flexible and reactive state management.

vuex

Vuex is a state management library specifically designed for Vue.js applications. It is similar to @ngrx/store in that it uses a centralized store, actions, and mutations (similar to reducers) to manage state. However, it is tightly integrated with Vue.js.

README

@ngrx/store

The sources for this package are in the main NgRx repo. Please file issues and pull requests against that repo.

License: MIT

Changelog

18.0.1 (2024-06-27)

Bug Fixes

• component-store: resolve issues in migration script to v18 (#4403) (a15d53e)
• effects: fix bugs in migration script to v18 (#4402) (6ae4723)
• eslint-plugin: only take return statement into account with no-multiple-actions-in-effects (#4410) (c9c646c), closes #4409

Features

• signals: rename signals to computed when defining custom features with input (#4395) (05f0940), closes #4391
• signals: replace idKey with selectId when defining custom entity ID (#4396) (67a5a93), closes #4217 #4392

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