redux-state-hook v1.2.0

redux-state-hook

A lightweight React hook to consume Redux state

Installation

Add it as a dependency to your package.json with

npm i --save redux-state-hook

or

yarn add redux-state-hook

Introduction

redux-state-hook requires React (v16.8.0+) and Redux (v3.0.0+). It is a non-invasive library, and aims to replace the use of React-Redux by providing a React hook instead of connected components - but it can be used alongside React-Redux without any problem.

To minimize component re-rendering, it's adviced to use a helper package when selecting state values, such as reselect.

API

<Provider store={reduxStore}>

The Provider-component manages the Redux store in it's own context. This component needs to be available in the component tree, to let useReduxState reach the actual Redux store.

useReduxState(selectorFn = null)

The hook itself takes an optional selectorFn which is a utility function to select a part of the Redux state tree. When selecting simple values such as numbers, strings, plain arrays or non-nested objects, useReduxState utilizes a shallow compare to reduce the number of component renders. For more complex data structures, a reselect selector can be used effectivly.

useReduxState returns a value pair, where the first value is the selected partial state, and the second value is the dispatch function from Redux. This function should be used to dispatch actions.

The selectorFn is an optional parameter, and when it's omitted the hook always returns a null value for the partial state return. This is useful when a component only need access to the dispatch function without caring about any state or state changes.

Example

There's a runnable, full scale, example available in the example directory.

Usage

app.js

import React from "react";
import { render } from "react-dom";
import { createStore, combineReducers } from "redux";
import { Provider } from "redux-state-hook";

const counter = (state = { count: 0 }, action) => {
    switch (action.type) {
        case "INCREASE": return { ...state, count: state.count + 1 };
        case "DECREASE": return { ...state, count: state.count - 1 };
        default: return state;
    }
};

const reducers = combineReducers({
    counter,
    ...
})
const store = createStore(reducers);

render(
    <Provider store={store}>
        <App />
    </Provider>,
    document.getElementById("app-root");
);

another-component.js

import React from "react";
import { createSelector } from "reselect";
import useReduxState from "redux-state-hook";

const countSelector = createSelector(
    state => state.counter.count,
    count => count
);

export const AnotherComponent = () => {
    const [ count, dispatch ] = useReduxState(countSelector);

    return (
        <>
            <span>Current count is <strong>{count}</strong></span>
            <div>
                <button onClick={() => dispatch({ type: "INCREASE" })}>Increase</button>
                <button onClick={() => dispatch({ type: "DECREASE" })}>Decrease</button>
            </div>
        </>
    );
};