Fragstore NPM | npm.io

Tiny, easy and powerful React state management library

What advantages does it have? ✨

Guide 🗺

Installation 🧑🏻‍💻

yarn add fragstore
# or
npm install fragstore --save

Init your store 👩🏽‍🎨

Each store has to be created with the createStore function. This function returns all the methods that you can use to consume and update the store properties.

createStore

import createStore from "fragstore";

const { useStore } = createStore();

Or also with an initial store:

const initialStore = {
  cart: { price: 0, items: [] },
};
const { useStore, getStore } = createStore(initialStore);

Or also with an event that is executed after every update:

const initialStore = {
  cart: { price: 0, items: [] },
};

function onAfterUpdate({ store, prevStore })
  console.log("This callback is executed after an update");
}

const { useStore } = createStore(initialStore, onAfterUpdate);

Input:

name	type	required	description
`initialStore`	`object<any>`	`false`	Object with your initial store.
`onAfterUpdate`	`function`	`false`	Function that is executed after each property change. More details.

Output:

name	type	description	example
`useStore`	`Proxy`	Proxy hook to consume and update store properties inside your components. Each time the value changes, the component is rendered again with the new value. More info.	`const [price, setPrice] = useStore.cart.price()`
`getStore`	`Proxy`	Similar to `useStore` but without subscription. You can use it as a helper outside (or inside) components. Note that if the value changes, it does not cause a rerender. More info.	`const [price, setPrice] = getStore.cart.price()`
`withStore`	`Proxy`	HoC with `useStore` inside. Useful for components that are not functional. More info.	`withStore.cart.price(MyComponent)`

How to export

We recommend using this type of export:

// ✅
export const { useStore, getStore, withStore } = createStore({
  cart: { price: 0, items: [] },
});

This way you can import it with:

// ✅
import { useStore } from '../store'

Avoid using a default export with all:

// ❌
export default createStore({ cart: { price: 0, items: [] } });

Because then you won't be able to do this:

// ❌  It's not working well with proxies
import { useStore } from '../store'

Manage the store 🕹

useStore hook

It's recommended to use the useStore hook as a proxy to indicate exactly what portion of the store you want. This way you only subscribe to this part of the store avoiding unnecessary re-renders.

import createStore from "fragstore";

const { useStore } = createStore({
  username: "Aral",
  count: 0,
  age: 31,
  cart: {
    price: 0,
    items: [],
  },
});

function Example() {
  const [username, setUsername] = useStore.username();
  const [cartPrice, setCartPrice] = useStore.cart.price();

  return (
    <>
      <button onClick={() => setUsername("AnotherUserName")}>
        Update {username}
      </button>
      <button onClick={() => setCartPrice((v) => v + 1)}>
        Increment price: {cartPrice}€
      </button>
    </>
  );
}

However, it's also possible to use the useStore hook to use all the store.

function Example() {
  const [store, setStore] = useStore();

  return (
    <>
      <button
        onClick={() =>
          setStore((s) => ({
            ...s,
            username: "AnotherUserName",
          }))
        }
      >
        Update {store.username}
      </button>
      <button
        onClick={() =>
          setStore((s) => ({
            ...s,
            cart: { ...s.cart, price: s.cart.price + 1 },
          }))
        }
      >
        Increment price: {store.cart.price}€
      </button>
    </>
  );
}

Input:

name	type	description	example
Initial value	`any`	This parameter is not mandatory. It only makes sense for new store properties that have not been defined before within the `createStore`. If the value has already been initialized inside the `createStore` this parameter has no effect.	`const [price, setPrice] = useStore.cart.price(0)`
event after an update	`function`	This parameter is not mandatory. Adds an event that is executed every time there is a change inside the indicated store portion.	`const [price, setPrice] = useStore.cart.price(0, onAfterUpdate)`And the function:`function onAfterUpdate({ store, prevStore }){ console.log({ store, prevStore }) }`

Output:

Is an Array with 3 items:

name	type	description	example
value	`any`	The value of the store portion indicated with the proxy.	A store portion `const [price] = useStore.cart.price()`All store: `const [store] = useStore()`
update value	`function`	Function to update the store property indicated with the proxy.	Updating a store portion:`const [count, setCount] = useStore.count(0)`Way 1:`setCount(count + 1)`Way 1:`setCount(c => c + 1)`-------Updating all store:`const [store, updateStore] = useStore()`Way 1:`updateStore({ ...store, count: 2 }))`Way 1:`updateStore(s => ({ ...s, count: 2 }))`
reset value	`function`	Function that reset the store property indicated with the proxy to their initial value.	Reset store portion:`const [,,resetCount] = useStore.count()resetCount()`Put counter to 0 again (initial value defined inside the `createStore`).-------Reset all store:`const [,,resetStore] = useStore()resetStore()`All store portions to their initial values.

getStore helper

It works exactly like useStore but with some differences:

It does not make a subscription. So it is no longer a hook and you can use it as a helper wherever you want.

It's not possible to register events that are executed after a change.

getStore.cart.price(0, onAfterPriceChange); // ❌

function onAfterPriceChange({ store, prevStore }) {
  // ...
}

If the intention is to register events that last forever, it has to be done within the createStore:

const { getStore } = createStore(initialStore, onAfterUpdate); // ✅

function onAfterUpdate({ store, prevStore }) {
  // ..
}

Very useful to use it:

Outside components: helpers, services, etc.
Inside components: Avoiding rerenders if you want to consume it inside events, when you only use the updaters const [, setCount, resetCount] = getStore.count(), etc.

Example:

import { useState } from "react";

const { getStore } = createStore({ count: 0 });

function Example1() {
  const resetStore = getStore()[2];
  return <button onClick={resetStore}>Reset store</button>;
}

function Example2() {
  const [newCount, setNewCount] = useState();

  function saveIncreasedCount(e) {
    e.preventDefault();
    const [count, setCount] = getStore.count();
    if (newCount > count) setCount(newCount);
    else alert("You should increase the value");
  }

  return (
    <form onSubmit={saveIncreasedCount}>
      <input
        value={newCount}
        onChange={(e) => setNewCount(e.target.valueAsNumber)}
        type="number"
      />
      <button>Save the increased count value</button>
    </form>
  );
}

withStore HoC

It's a wrapper of the useStore for non-functional components. Where you receive the same thing that the useStore hook returns inside this.props.store.

Example with a store portion:

const { withStore } = createStore();

class Counter extends Component {
  render() {
    const [count, setCount, resetCount] = this.props.store;
    return (
      <div>
        <h1>{count}</h1>
        <button onClick={() => setCount((v) => v + 1)}>+</button>
        <button onClick={() => setCount((v) => v - 1)}>-</button>
        <button onClick={resetCount}>reset</button>
      </div>
    );
  }
}

// Similar to useStore.counter.count(0)
const CounterWithStore = withStore.counter.count(Counter, 0);

Example with all store:

const { withStore } = createStore({ count: 0 });

class Counter extends Component {
  render() {
    const [store, setStore, resetStore] = this.props.store;
    return (
      <div>
        <h1>{store.count}</h1>
        <button onClick={() => setStore({ count: store.count + 1 })}>+</button>
        <button onClick={() => setStore({ count: store.count - 1 })}>-</button>
        <button onClick={resetStore}>reset</button>
      </div>
    );
  }
}

// Similar to useStore()
const CounterWithStore = withStore(Counter);

The only difference with the useStore is that instead of having 2 parameters (initialValue, onAfterUpdate), it has 3 where the first one is mandatory and the other 2 are not (Component, initialValue, onAfterUpdate).

Register events after an update 🚦

It is possible to register an event after each update. This can be useful for validating properties, storing error messages, optimistic updates...

There are 2 ways to register:

Permanent events: Inside createStore. This event will always be executed for each change made within the store.

export const { useStore, getStore } = createStore(
  initialStore,
  onAfterUpdate
);

function onAfterUpdate({ store, prevStore }) {
  // Add an error msg
  if (store.count > 99 && !store.errorMsg) {
    const [, setErrorMsg] = getStore.errorMsg();
    setErrorMsg("The count value should be lower than 100");
    return;
  }
  // Remove error msg
  if (store.count >= 99 && store.errorMsg) {
    const [, setErrorMsg] = getStore.errorMsg();
    setErrorMsg();
  }
}

Temporal events: Inside useStore / withStore. These events will be executed for each change in the store (or indicated portion) only during the life of the component, when the component is unmounted the event is removed.

function Count() {
  const [count, setCount] = useStore.count(0, onAfterUpdate);
  const [errorMsg, setErrorMsg] = useStore.errorMsg();

  // The event lasts as long as this component lives
  function onAfterUpdate({ store, prevStore }) {
    // Add an error msg
    if (store.count > 99 && !store.errorMsg) {
      setErrorMsg("The count value should be lower than 100");
      return;
    }
    // Remove error msg
    if (store.count >= 99 && store.errorMsg) {
      setErrorMsg();
    }
  }

  return (
    <>
      {errorMsg && <div className="erorMsg">{errorMsg}</div>}
      <div className="count">{count}</div>
      <button onClick={() => setCount((v) => v + 1)}>Increment</button>
    </>
  );
}

How to... 🧑‍🎓

Add a new store property

You can use useStore / getStore / withStore even if the property does not exist inside the store, and create it on the fly.

const { useStore } = createStore({ username: "Aral" });

function CreateProperty() {
  const [price, setPrice] = useStore.cart.price(0); // 0 as initial value

  return <div>Price: {price}</div>;
}

function OtherComponent() {
  // store now is { username: 'Aral', cart: { price: 0 } }
  const [store] = useStore();
  console.log(store.cart.price); // 0
  // ...
}

It's not mandatory to indicate the initial value, you can create the property in a following step with the updater.

const { useStore } = createStore({ username: "Aral" });

function CreateProperty() {
  const [cart, setCart] = useStore.cart();

  useEffect(() => {
    initCart();
  }, []);
  async function initCart() {
    const newCart = await fetch("/api/cart");
    setCart(newCart);
  }

  if (!cart) return null;

  return <div>Price: {cart.price}</div>;
}

Reset a store property

You can use the 3th array item from useStore / getStore / withStore. It's a function to return the value to its initial value.

const [item, setItem, resetItem] = useStore.item();
// ...
resetItem();

If you only want the reset function and not the value, we recommend using the getStore to avoid creating a subscription and avoid unnecessary rerenders.

const [, , resetItem] = getStore.item();
// or...
const resetItem = getStore.item()[2];

Reset all the store

The same thing works to reset the entire store to its initial value.

const [store, setStore, resetStore] = useStore();
// ...
resetStore();

Use more than one store

You can have as many stores as you want. The only thing you have to do is to use as many createStore as stores you want.

store.js

import createStore from "fragstore";

export const { useStore: useCart } = createStore({ price: 0, items: [] });
export const { useStore: useCounter } = createStore({ count: 0 });

Cart.js

import { useCart } from "./store";

export default function Cart() {
  const [price, setPrice] = useCart.price();
  // ... rest
}

Counter.js

import { useCounter } from "./store";

export default function Counter() {
  const [count, setCount] = useCounter.count();
  // ... rest
}

Update several portions avoiding rerenders in the rest

If you do this it causes a rerender to all the properties of the store:

// 😡
const [store, setStore] = useStore();
setStore({ ...store, count: 10, username: "" });

And if you do the next, you convert the whole store into only 2 properties ({ count: 10, username: '' }), and you will remove the rest:

// 🥵
const [store, setStore] = useStore();
setStore({ count: 10, username: "" });

If you have to update several properties and you don't want to disturb the rest of the components that are using other store properties you can create a helper with getStore.

export const { useStore, getStore } = createStore(initialStore);

export function setStore(fields) {
  Object.keys(fields).forEach((key) => {
    const setStoreField = getStore[key]()[1];
    setStoreField(fields[key]);
  });
}

And use it wherever you want:

// 🤩
import { setStore } from "./store";

// ...
setStore({ count: 10, username: "" });

Define calculated properties

It's possible to use the getStore together with the function that is executed after each update to have store properties calculated from others.

In this example the cart price value will always be a value calculated according to the array of items:

export const { useStore, getStore } = createStore(
  {
    cart: {
      price: 0,
      items: [],
    },
  },
  onAfterUpdate
);

function onAfterUpdate({ store }) {
  const { items, price } = store.cart;
  const calculatedPrice = items.length * 3;

  // Price always will be items.length * 3
  if (price !== calculatedPrice) {
    const [, setPrice] = getStore.cart.price();
    setPrice(calculatedPrice);
  }
}