Subscribe

What is subscribe?

with subscribe function you will be notified whenever there is a change by simply

const unsubscribe = store.subscribe(state => {
    console.log('state updated!')
})

And when you want to stop it just use the returned function

unsubscribe()

Filter

Sometimes you want to only be notified if some of the properties changed, you can use the getter option, which returns a derived state from store.

const countStore = reim({
    count: 2,
    message: ''
})

countStore.subscribe(state => {
    console.log('state count changed!')
    console.log(state.count) // 12
    console.log(state.messsage) // undefined
}, {
    filter: state => ({count: state.count})
})

// Will not trigger subscriber
countStore.setState({message: 'should not trigger'})

// 'state count changed'
countStore.setState(state => {
    state.count += 10
})