redux-store-observe

Redux Store observer

Why?

Redux provides you with a subscribe() method so that you can be notified when the state changes. However, it does not let you know what changed or subscribe to partial slices of the store. redux-store-observe will let you do that, also with custom equality functions. redux-store-observe completely supports typescript and reflects the types of your state.

Install

npm i --save redux-store-observe

Usage

import store from './store'
import createStoreObserver from 'redux-store-observe'

let observer = createStoreObserver(store)

const unsubscribe1 = observer.observe(
  (state) => state.account.id,
  (value) => console.log(id)
)

const unsubscribe2 = observer.observe(
  (state) => state.account.invoices,
  (value) => console.log(invoices),
  (prevValue, nextValue) => prevValue.length === nextValue.length
)

unsubscribe1()
unsubscribe2()

Note on Comparisons

By default, redux-store-observe uses === (strict equal) operator to check for changes. This may not be want you want. Sometimes you may want to do a deep inspection. You can use custom equality functions or use either deep-equal (substack/node-deep-equal) or is-equal (ljharb/is-equal). is-equal is better since it supports ES6 types like Maps/Sets.

License

MIT