Redux Composite

Composing high-level Labelled transition system from small ones.

✅ The library allows low-level system implementations being independent from the high-level system structure. This way low-level systems could be re-usable in different high-level systems.

Motivation

Imagine, we have a simple reducer

const Reducer = (state, action) => {
    if (state === undefined) {
        return {clicked: false};
    }
    switch (action.type) {
        case 'CLICK':
            return {clicked: true};
        case 'ENABLE':
            return {clicked: false};
        default:
            return state;
    }
};

We can easily use this reducer in Redux with createStore. But what if now we need to update our global state having array of 2 these states? Like [{clicked: bool}, {clicked: bool}].

I can't do combineReducers({first: Reducer, second: Reducer}) - because both have the same action types. Without changing reducer it seems like not possible. Moreover, I may have a middleware, using dispatch expecting this data structure, not the array of 2. Modifying reducers and middlewares may not be good solution. It could be package library, that you don't want to change.

Solution

Within Redux Composite you simply have composite state-manager like this: Structure([Reducer, Reducer]).

Or if with Middleware, we define it like:

Structure([
    Composite({reducer: Reducer, middleware: Middleware}),
    Composite({reducer: Reducer, middleware: Middleware})
])

And here how it looks in action:

• buttons do not know about global state structure
• original reducer and middleware are used for each button

Demo

https://github.com/blackakula/redux-composite-demo/

Documentation

State

• Documentation
• Example

Dispatch

• Documentation
• Example

Subscribe

• Documentation
• Example

Memoize

• Documentation
• Example

Composite

• Documentation

createStore

• Documentation