React Motive

Small wrapper around the React Context API with actions/dispatch style state management.

Install

yarn add react-motive

Example

import React from 'react';
import createMotive from 'react-motive';

/**
 * Default State
 */
const defaultState = { count: 0 };

/**
 * Actions:
 *
 * Actions don't have to be curried functions if they don't take arguments
 * as long as dispatch is given a function that returns a new slice of state.
 */
const increment = () => ({ count }) => ({
  count: count + 1,
});

const decrement = () => ({ count }) => ({
  count: count - 1,
});

/**
 * Create Container
 */
const Counter = createMotive(defaultState);

/**
 * Use Consumers
 */
const Display = () => (
  <Counter.Consumer>
    {({ state }) => <h1>Count: {state.count}</h1>}
  </Counter.Consumer>
);

const Controls = () => (
  <Counter.Consumer>
    {({ dispatch }) => (
      <React.Fragment>
        <button onClick={() => dispatch(decrement())}>-</button>
        <button onClick={() => dispatch(increment())}>+</button>
      </React.Fragment>
    )}
  </Counter.Consumer>
);

/**
 * Put it all together
 */
const AllTogether = () => (
  <Counter.Provider>
    <Display />
    <Controls />
  </Counter.Provider>
);

Documentation

createMotive

createMotive returns an object with a Provider component and a Consumer component.

const defaultState = { count: 1 };

const { Provider, Consumer } = createMotive(defaultState);

<Provider>

The Provider is a React component that should wrap all of its corresponding Consumer components. This component holds all of the state given from defaultState and that is updated later on.

<Consumer>

The Consumer component is what you can use anywhere as long as it's a child of the corresponding Provider component. Use this component to get access to the state of its Provider and to dispatch updates to that state.

<Consumer>
  {({ state, dispatch }) => /* ... some react stuff that uses state or dispatch */ }
</Consumer>

This component takes a render prop as its child. This render prop is given an object with the following members in it.

state

This is the current state of the corresponding Provider component.

dispatch

dispatch should be called with an action function. An action should return a slice of new state to be merged into the Provider's state.

Actions

Actions are provided with state and dispatch as arguments. This means you can dispatch other actions from an action if necessary.

An action must return a partial version of state.

Pro Tip: If you need to give actions data, write them as curried functions and call them into dispatch with any arugments that they might need.

/**
 * Basic action
 */
const increment = (state) => ({
  count: state.count + 1,
});

dispatch(increment);

/**
 * Curried action that takes arguments
 */
const incrementBy = (incrBy) => (state) => ({
  count: state.count + incrBy,
});

dispatch(incrementBy(2));

/**
 * Action that dispatches another action
 */
const delayedIncrement = (state, dispatch) => {
  setTimeout(() => dispatch(incrementBy(2)));

  return {
    count: state.count + 1,
  };
};

dispatch(delayedIncrement);

combineActions

combineActions will take two actions and combine their returned updated pieces of state into one updated piece of state.

const defaultState = {
  a: 0,
  b: 0,
};

const actionA = (state) => {
  return {
    a: state.a + 1,
  };
};

const actionB = (state) => ({
  b: state.b + 2,
});

const combined = combineActions(actionsA, actionB);

const resultingState = dispatch(combined);

resultingState === { a: 1, b: 2 };