Lean Redux

Redux state like local component state.

Design

• Basic Redux state access and updating should be simple as it is with the component local state
  • No need to manually create action types or reducers
  • The same API with React Components! Use this.setState() to update Redux state
• Redux state is be scoped to the components
  • Component cannot interfere with parts of the state that do not belong to it
• Play well with other tools in the Redux community
  • Time travel debuggers, state serialization tools, Redux Form etc. work well with Lean Redux
  • You can drop this into your existing project and start using it only for parts of the app
• Good performance
  • Lean Redux is build on top of the new connectAdvanced() primitive of React Redux 5.0 and implements the same optimizations as connect()
  • Handlers are automatically bound to avoid some pure render anti-patterns

Example

import {connectLean} from "lean-redux";

var Counter = ({count, handleClick}) => (
    <div>
        {count} <button onClick={handleClick}>+1</button>
    </div>
);
Counter = connectLean({
    getInitialState() {
        return {count: 0};
    },
    handleClick(e) {
        e.preventDefault();
        this.setState({count: this.state.count + 1});
    },
})(Counter);

// Scope it to a myCounter key in the Redux state
// <Counter scope="myCounter" />

To learn more checkout the live examples.

Setup

yarn add lean-redux

or

npm install --save lean-redux

Just add the leanReducer to your store and start creating components with connectLean.

import {createStore, applyMiddleware} from "redux";
import {Provider} from "react-redux";
import {leanReducer} from "lean-redux";

const store = createStore(leanReducer);

var Main = () => (
    <Provider store={store}>
        <Counter />
    </Provider>
);

ReactDOM.render(<Main />, document.getElementById("app"));

If you already have other reducers you can merge leanReducer into them with the composeReducers helper:

import {leanReducer, composeReducers} from "lean-redux";

const store = createStore(composeReducers(myReducer, myAnotherReducer, leanReducer));

Checkout the index.js in examples for complete example.

Usage with the Redux combineReducers helper

The combineReducers helper function does not like dynamically generated top level state keys so Lean Redux must be scoped under a specific key in the Redux state when used with the combineReducers helper.

import {createStore, combineReducers} from "redux";
import {leanReducer} from "lean-redux";

leanReducer.setGlobalScope("lean");

const store = createStore(combineReducers({
    lean: leanReducer
}));

API

Functions exported by the lean-redux module.

connectLean(options: Object): (component: ReactComponent) => ReactComponent

Connects a React component to a Redux store. Like connect() in React Redux it does not modify the component but returns a new one.

options

• scope: string|Array|Function Scope the component to a part of the Redux state. Deep scopes can be defined with arrays. Missing path values in the state will be automatically created as objects. If the value is a function it should return the final scope. Parent component props are passed to the function. If scope is passed as a prop from the parent component it will override the value defined here unless it's a function.
• getInitialState(): Object Create default values for the scoped state. Like React component getInitialState() this is executed only once when the component is mounted.
• mapState(state: Object, ownProps: Object): Object Modify the state before passing it to the wrapped component. Just like the mapStateToProps in React Redux, but the state is scoped according to the scope option. If not defined the default implementation is to return the props matching what getInitialState() returns.
• defaultProps: Object Default props for the handler context.

Any other methods are considered to be "handlers" and are passed to the wrapped component as props.

handlerContext

The context, this, in the handlers is like in the React Components.

• this.state: Object The current scoped state from Redux
• this.props: Object Props from defaultProps and any additional props passed by the parent component.
• this.setState(function|object nextState, [function callback]) Function to update the scoped Redux state. The API is exactly the same with the React Component setState().
• this.dispatch: Function Redux store dispatch