ngrx-immer

Immer wrappers around NgRx methods to mutate state easily

Installation

npm install ngrx-immer

Do not forget to install immer

Resources

• Immer docs
• NgRx docs

createImmerReducer

Creates an NgRx reducer, but allows you to mutate state without having to use to spread operator.

• Use it when you want to go Immer all the way
• Caveat, you have to return the state with each on method

import { createImmerReducer } from 'ngrx-immer/store';

const todoReducer = createImmerReducer(
	{ todos: [] },
	on(newTodo, (state, action) => {
		state.todos.push({ text: action.todo, completed: false });
		return state;
	}),
	on(completeTodo, (state, action) => {
		state.todos[action.index].completed = true;
		return state;
	}),
);

immerOn

Creates an NgRx reducer, but allows you to mutate state without having to use to spread operator.

• Use it when you want to go sprinkle a little bit of Immer for more complex cases

import { immerOn } from 'ngrx-immer/store';

const todoReducer = createReducer(
	{ todos: [] },
	on(newTodo, (state, action) => {
		return {
			...state,
			todos: [...state.todos, action.todo],
		};
	}),
	immerOn(completeTodo, (state, action) => {
		state.todos[action.index].completed = true;
	}),
);

ImmerComponentStore

Wraps Immer around the Component Store updater and setState methods.

import { ImmerComponentStore } from 'ngrx-immer/component-store';

@Injectable()
export class MoviesStore extends ImmerComponentStore<MoviesState> {
	constructor() {
		super({ movies: [] });
	}

	readonly addMovie = this.updater((state, movie: Movie) => {
		state.movies.push(movie);
	});
}

immerReducer

Inspired by Alex Okrushko, immerReducer is a reducer method that uses the Immer produce method. This method is used by all of the methods in ngrx-immer provides.

Migrating from ngrx-etc to ngrx-immer

You can execute the following script in your project, this script replaces everything from ngrx-etc to the ngrx-immer equivalent.

npx https://gist.github.com/timdeschryver/efdded8b72bd36ac0a2bc719eca1f161

Don't forget to install ngrx-immer and immer after running the above script.

Old (ngrx-etc)	New (ngrx-immer)
mutableOn	immerOn
createMutableReducer	createImmerReducer
	ImmerComponentStore
	immerReducer

FAQ

• See the Immer docs, Update patterns, on how to mutate state