Stores

Signals are great for single values; a store is for nested, structured state. createStore returns a reactive proxy and a setter, with fine-grained tracking down to individual properties:

import { createStore } from '@fluixi/reactive/store';

const [cart, setCart] = createStore({
  items: [] as Item[],
  total: 0,
});

cart.total;            // read a property reactively
setCart('total', 42);  // update one property — only readers of total re-run

Path updates

The setter takes a path to the property you want to change, so reads of unrelated branches stay untouched:

setCart('items', items => [...items, newItem]);
setCart('items', 0, 'qty', q => q + 1); // nested path

A reader of cart.total is not disturbed by a write to cart.items — that is the point of a store over a single signal holding an object.

Reading in computations

Reading a store property inside a memo or effect subscribes to just that property:

const itemCount = createMemo(() => cart.items.length); // tracks items only

Next: Async data.