npm i picostate --save

Event-based immutable state management.

• 400 bytes
• familiar event based interface
• only fires listeners for changed values
• emits state updates only when requested
• integrates seamlessly with React

Usage

Create a store:

import createStore from "picostate";

const store = createStore({
  a: 0,
  b: false
});

Safely access state:

store.state; // { a: 0, b: false }

Register a listener for any state changes:

store.listen(state => console.log(state));

Register a listener only for changes to an array of props, in this case b:

store.listen(["b"], state => console.log(state.b));

Update state:

const emit = store.hydrate({ a: 1 });

Fire registered listeners:

emit(); // { a: 1, b: false }

Update state and fire listeners:

store.hydrate({ b: true })(); // { a: 1, b: true }, true

Update state using the previous state:

store.hydrate(state => ({ a: state.a + 1 }))(); // { a: 2, b: true }

const removeListener = store.listen(state => console.log(state));
store.hydrate({ a: 1 })(); // { a: 1, b: true }
removeListener();
store.hydrate({ a: 2 })(); // no listener fired
store.state; // { a: 2, b: true }

Reset to initial state:

store.hydrate();
store.state; // { a: 0, b: false }

License

MIT License © Eric Bailey