observable-state-store
Simple observable state store.
Features
- Clear state definitions
- Clear action definitions
- Observable
- Simple to use and maintain
Installation
npm i --save observable-state-store
Usage
import Store from 'observable-state-store'
// define state
const state = {
count: 0
}
// define actions
const actions = {
inc: (state, number) => Object.assign({}, state, {count: state.count + number})
}
// create store
const store = new Store({state, actions})
// subscribe to the state
const subscription = store.subscribe((newState, oldState) => {
if (newState.count > oldState.count) {
console.log('count inc!')
}
});
// execute action
store.actions.inc(-2); // nothing
store.actions.inc(3); // print 'count inc!'
// stop subscription
subscription.stop();
store.actions.inc(2); // nothing
APIs
Store
constructor(options)
options is an object with fields
- state
- actions
state can be anything,
but we recommend to use Immutable.js
or similar things as your state.
actions are functions grouped into an object.
The signature of any action is
function(oldState, ...args): newState
Inside the action body, you should not modify the old state directly. Instead, you should create and return an new state.
subscribe(observer): subscription
Subscribe to the store, and get notified by any execution of the actions.
observer is an function with the signature
function(newState, oldState)
You should not modify either newState or oldState.
Call subscription.stop() to stop the subscription.
actions
actions are mapped from the actions you passed into the constructor
with new signature
function(...args)
For example, if you passed into constructor such an action
{
inc: (state, number) => Object.assign({}, state, {count: state.count + number})
}
then you can call the corresponding version of action on the store this way
store.actions.inc(3)
getState(): state
Get current state directly. You should not modify the state it returns.