get-set-immutable

get-set-immutable makes it easy to update immutable objects similar to Immer but up to 5 times faster. It can be used inside redux or zustand where it's difficult to work with large complex deeply nested objects. You can also use it as a independent store for any type of js application.

Installation

You can install get-set-immutable via npm:

npm install get-set-immutable

Usage

Check out the example along with benchmarks here:

Here is an example on how you can use i to mutate immutable objects.

import { i } from "get-set-immutable";

const obj = { count: 0, address: { street: "" } };

i(obj).set({ count: 1, address: { street: "street name" } }); // { count: 1, address: { street: "" } }
i(obj).set((s) => ({ count: 1, address: { street: "street name" } })); // { count: 1, address: { street: "" } }
i(obj).update((s) => {
  s.count = 1;
  s.address.street = "street name";
}); // { count: 1, address: { street: "" } }

Here is an example of using i inside redux reducer to change the state as you change a js object.

function countReducer(state = initialState, action: ActionTypes): CountState {
  switch (action.type) {
    case INCR:
      return i(state).update((s) => s.count++);
    case DECR:
      i(state).update((s) => s.count--);
    default:
      return state;
  }
}

here is how you can use it as a store.

import { i } from "get-set-immutable";

// Create a get-set-immutable instance with initial state. i -> immutable obj. you can also pass primitives if you need to.
const stateWithoutActions = i({
  count: 0,
  address: { street: "" },
  countDoubled: 0,
});

const stateWithActions = i(
  {
    count: 0,
  },
  ({ get, update }) => ({
    incr() {
      update((s) => s.count++);
    },
  })
);

// Subscribe to state changes and log the count whenever it changes
state.subscribe((changes) => {
  console.log("State changed:", changes);
});

// Update the count state
state.set({ count: 1 });
// or
state.set((s) => ({ ...s, count: s.count + 1 }));
// update portion of the state, will re-create parent refs. similar to immer.
state.update((state) => {
  state.address.street = "new street";
});

// react to specific changes
state.react(
  (state) => {
    state.countDoubled = state.count * 2;
  },
  // pass a function as second param that returns dependency array
  (state) => [state.count]
);

Examples

Subscribing to State Changes

// Subscribe to state changes
const unsub = state.subscribe((changes) => {
  console.log("State changed:", changes);
});

Updating State

Reacting to State Changes with Dependencies

this is useful when you want to react to state changes. you can listen to entire state or you can listen to portion of it. you can also update state in reaction call back which gets the updated state, and if you want to change the state, you can access state instance's set or update methods.

// React to state changes with dependencies
state.react(
  (s) => {
    // if you want to change the state, you can do that like this:
    s.countDoubled = s.count * 2;
    console.log("Count changed:", s.count);
  },
  (s) => [s.count]
);

API

create(initialState: object): object

Creates a new get-set-immutable instance with the provided initial state.

• initialState: An object representing the initial state.

Returns an object with the following methods:

• set(newState: object | (currentState: object) => object): object: Updates the whole state with the provided new state object or a function that returns a new state object based on the current state.

• update(newState: object | (currentState: object) => void): object: updates the portion of the state.

• subscribe(callback: (changes: Change[]) => void): unsubFn: Subscribes to state changes. The callback function will be called whenever the state changes, and it receives an object containing the changes. returns unsubcribe function when called, will remove subscription.

• react(effectFn: (state: object) => void, dependencyArrayFn: (state: object) => any[]): void: Similar to React's useEffect. It takes an effect function and a dependency array function. The effect function is called when the dependencies change.