Core Concepts

Access to state is scoped by get and set.

Code inside a set function has read and write access to state values.

Live Editor

import { set } from "carry-on-store"; const storeId = "coreSetExample"; set(storeId, state => { state.field1 = 1; state.field2 = 2; }); render(<StateInspector from={storeId} />);

import { set } from "carry-on-store";

const storeId = "coreSetExample";

set(storeId, state => {
  state.field1 = 1;
  state.field2 = 2;
});

render(<StateInspector from={storeId} />);

Result

Loading...

Values can be read inside a get function.

Live Editor

import { get, set } from "carry-on-store"; const storeId = "coreGetExample"; set(storeId, state => { state.field1 = 1; state.field2 = 2; }); const values = get(storeId, state => [state.field1, state.field2]); // values === [1, 2] render(<StateInspector from={storeId} />);

import { get, set } from "carry-on-store";

const storeId = "coreGetExample";

set(storeId, state => {
  state.field1 = 1;
  state.field2 = 2;
});

const values = get(storeId, state => [state.field1, state.field2]);
// values === [1, 2]

render(<StateInspector from={storeId} />);

Result

Loading...

The state container is synchronous.

Execute asynchronous code outside of get and set scopes.

State.render maps to a specialized get scope.

The State component uses a specialized get scope that tracks field access. When changes to the tracked fields are detected, the component is rerendered.

State.render is batched

Each State component affected by a state change will batch update using React's unstable_batchedUpdates facility.

State is initially registered with an unconnected state container.

No access or mutation can occur until the container is connected. The state container is connected by a call to connect, get, or set.

Initial registrations are queued until the container is connected. Queued registrations are processed in the order specified by the state's priority key.

The reason a container is initially unconnected is to allow for deterministic registration of middleware registered out of order.