cornflux

cornflux

A library for dispatching events in a React application using the react context as a data bus.

The goal of this library is to achieve a layer of data isolation where application state is confined to "data components" that can only be interfaced with by other components via action functions.

The longer version can be found in this post on medium if you have the patience.

Installation

# make sure you have the dependencies first:
npm install --save react react-dom
npm install --save cornflux

The source code is not transpiled; you will need a transpiler like Babel.js to consume it. However, a built-version is provided under dist/ but it expects React and ReactDOM to be available on window.

Usage

There are two conceptual types provided by the library; action providers and action emitters.

Action providers are components that perform actions, while action emitters are ones that request an action be performed.

Handling actions

Use the ActionProvider decorator to construct a version of the component that is able to receive action requests and carry them out.

import { ActionProvider } from 'cornflux';
import DataConsumer from './DataConsumer';

const DataProvider = React.createClass({
  getInitialState() {
    return { count: 0 };
  },

  render() {
    return <DataConsumer count={this.state.count}
  }
});

const ActingDataProvider = ActionProvider(DataProvider, {
  actions: [
    ADJUST_COUNT(component, payload) {
      component.setState({ count: payload.count });
    }
  ]
});

export default MyActingComponent;

Triggering actions

Use the ActionEmitter decorator to construct a version of a component that needs to dispatch action requests. You must explicitly specify which actions the component is allowed to dispatch.

import { ActionEmitter } from 'cornflux';

const DataConsumer = React.createClass({
  render() {
    return React.createElement('button', {
      onClick: this.incrementCounter
    });
  },

  incrementCounter() {
    this.props.dispatch('ADJUST_COUNT', { count: this.props.count + 1 });
  }
});

const EmittingDataConsumer = ActionEmitter(DataConsumer, {
  actions: [
    'ADJUST_COUNT'
  ]
});

export default EmittingDataConsumer;

That's really it. What you use for storing and manipulating data is of no relevance to cornflux. You can use Redux, Ember, Backbone, or whatever you want.

API Reference

ActionProvider: (Component, options: Object) -> Component

The options are as follows:

!actions: Object.<{ String, Function }>

The actions that are provided by the component. The keys are the action identifiers (and that's what emitters will be using to request it) and the values are the actual handlers.

The handler signature is as such:

(
  state: Object,
  payload: ...Any,
  delegate: {
    dispatch: (String, Object) -> Any,
    propagate: () -> Any
  }
) -> Promise

The first argument, state, is either the reduced state of the container if reduce was defined, otherwise it's the component instance itself.

The payload argument is the action payload that was provided when the action was emitted. It is "spread out" to as many arguments the dispatch call was provided by an emitter (vararg).

The last argument is an object containing two functions:

• dispatch to dispatch other events to the same provider. The signature is is similar to emitter's dispatch.
• propagate to yield (or "bubble") the action to a provider higher in the tree. Note that it accepts NO parameters; the action is yielded as-is.

?reduce: (component) -> Object

Given the rendered component instance, generate the state to pass to action handlers.

Defaults to: the identity function where the component instance itself is passed through (which exposes props, state, setState, etc.)

ActionEmitter: (Component, options: Object) -> Component

!actions: Array.<String>

The list of actions that the component is expected to emit. At run-time, the actions you list will be verified to be provided by some ActionProvider up the tree, otherwise a warning will be logged.

?propName: String

The name of the prop that will be passed down to the decorated component to use for dispatching actions.

Defaults to: dispatch

License

The MIT license.