ngrx-store-freeze/README.md

@ngrx/store meta reducer that prevents state from being mutated.

## ngrx-store-freeze

[![npm version](https://badge.fury.io/js/ngrx-store-freeze.svg)](https://badge.fury.io/js/ngrx-store-freeze)
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ngrx-store-freeze is a meta-reducer that prevents state from being mutated

* Recursively freezes the **current state**, the dispatched **action payload** if provided and the **new state**.
* When mutation occurs, an exception will be thrown.
* Should be used **only in development** to ensure that the state remains immutable.


### Installation

```sh
npm i --save-dev ngrx-store-freeze
```

OR

```sh
yarn add ngrx-store-freeze --dev
```

### Setup

```ts
import { StoreModule, MetaReducer, ActionReducerMap } from '@ngrx/store';
import { storeFreeze } from 'ngrx-store-freeze';
import { environment } from '../environments/environment'; // Angular CLI environment

export interface State {
  // reducer interfaces
}

export const reducers: ActionReducerMap<State> = {
  // reducers
}

export const metaReducers: MetaReducer<State>[] = !environment.production ? [storeFreeze]: [];

@NgModule({
  imports: [
    StoreModule.forRoot(reducers, { metaReducers }),
  ]
})
export class AppModule {}
```

## Additional Documentation

* [Usage with `@ngrx/router-store`](./docs/docs.md#router-store-compatibility)

## Credits

[redux-freeze](https://github.com/buunguyen/redux-freeze) - Redux middleware that prevents state from being mutated  
[Attila Egyed](https://github.com/tsm91) - The original maintainer of this project