Flex-reducer NPM

Flex Reducer

Nice and flexible React app state manager.

React app state management can be pretty nice. Use useFlexReducer in a component as a regular useReducer react hook. Its data will be available for all other components via useSelector hook until the reducer owner (component where useFlexReducer was called) unmounted. You can use multiple useFlexReducer and useSelector hooks without extra renders.

Advantages over official Redux.

No global store data always available for any component not related to.
Allows to separate data for every logical page, no reducers combining.
It doesn't use React context, no need to create and provide it.
You can use dispatch out of a component.
Small code base just about 130 lines you can figure out.

Installation

Flex Reducer requires React 16.8.3 or later.

# If you use npm:
npm install flex-reducer

# Or if you use Yarn:
yarn add flex-reducer

Usage

import { useFlexReducer, useSelector, dispatch } from 'flex-reducer';

// useFlexReducer (the 4th argument is optional, by default cache set to true)
const [state, dispatch] = useFlexReducer('app', reducer, initialState, { cache: false });
const todos = state.todos;

// useSelector (equality function is optional)
const todos = useSelector(state => state.app.todos, equalityFn?);

// dispatch (you can use it right in action definition)
const updateAction = (payload) => dispatch({
  type: 'UPDATE',
  payload,
});

If you set cache to false the reducer's data will be reset to initial on the component next mount.

You can use multiple useFlexReducer to separate your app data and take it via useSelector by its reducer name. Let's say a user data should be global and available for every page. Just call useFlexReducer('user', reducer, initialState) in your root component and you can use its data in every page component like const user = useSelector(state => state.user). On a user action dispatch the useFlexReducer and useSelector will call rerender of its components. It is very possible that every page also has its own data, just use useFlexReducer('pageName',...) in every page component and its data will be available but only if the page has been rendered. This approach allows to avoid using wrong/outdated data from the page/component which isn't at work or mistakenly change its data.

Example

// index.js
import TodoApp from "./TodoApp";

const rootElement = document.getElementById("root");
ReactDOM.render(
  <TodoApp />,
  rootElement
);

// TodoApp.js
import { useFlexReducer } from 'flex-reducer';
import AddTodo from './AddTodo';
import TodoList from './TodoList';
import { setInput } from './actions';

export default function TodoApp() {
  const [state] = useFlexReducer('app', reducer, initialState);
  return (
    <div className="todo-app">
      <h1>{state.title}</h1>
      <input value={state.input} onChange={e => setInput(e.target.value)} />
      <AddTodo />
      <TodoList />
    </div>
  );
}

// AddTodo.js
import { useSelector } from 'flex-reducer';
import { addTodo, setInput } from "./actions";

const genId = () => Math.rand();

export default const AddTodo = () => {
  const content = useSelector(state => state.app.input);
  function handleAddTodo() {
    if (content) {
      addTodo({ id: genId(), content });
      setInput('');
    }
  }
  return (
      <button onClick={handleAddTodo}>
        Add Todo
      </button>
  );
}

// actions.js
import { dispatch } from 'flex-reducer';

export const SET_INPUT = 'SET_INPUT';
export const ADD_TODO = 'ADD_TODO';

export const setInput = (value) => dispatch({
  type: SET_INPUT,
  payload: value
});
export const addTodo = (id, content) => dispatch({
  type: ADD_TODO,
  payload: { id, content }
});

For more detailed example check todos app.