redux-watch
Watch/observe Redux store state changes.
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. redux-watch
will let you know what changed.
Install
npm i --save redux-watch
Usage
watch(getState [, objectPath [, comparison]])
-> function
getState
: Afunction
that is used to return the state. Also useful in conjunction with selectors.objectPath
: An optionalstring
orArray
that represents the path in an object. Uses object-path (mariocasciaro/object-path) for value extraction.comparison
: An optional function to pass for comparison of the fields. Defaults to strict equal comparison (===
).
Example
basic example
// ... other imports/requires // assuming you have an admin reducer / state sliceconsole // 'JP' // store is THE redux storelet w = store // somewhere else, admin reducer handles ADMIN_UPDATEstore
reselect (reactjs/reselect) selectors)
example (w/When using with selectors, you often times won't need to pass the object path. Most times the selectors will handle this for you.
// ... other imports requires // assuming mySelector is a reselect selector defined somewherelet w = store
Note on Comparisons.
By default, redux-watch
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 should 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.
deep equal example
let w = store
License
MIT
Copyright (c) JP Richardson