react-tunnel

React components and decorators for putting context-like values into context and pulling them out as props

Heavily copied/modeled off the code used in react-redux by @gaearon

Table of Contents

• Installation
• React Native
• Quick Start
• Best Practices
• API
  • <Provider {...props}>
  • inject([mapProvidedToProps])
• Thanks
• License

installation

npm install --save react-tunnel.

React Native

for React: require/import from react-tunnel.
For React Native: require/import from react-tunnel/native.

Quick Start

react-tunnel helps you provide injectable props to child components to help avoid deep chains of prop passing

• install with npm install react-tunnel
• import or require Provider and inject by

//es5
var Provider = require('react-tunnel').Provider;
var inject = require('react-tunnel').inject;

//es6
import { Provider, inject } from 'react-tunnel'

• wrap a Component tree with <Provider provide={fn|object}> like

//using object provide
render() {
    return (
        <Provider provide={{thing: "one", anotherThing: 2}}>
            {(function () {
                return <Anything>
            })}
        </Provider>
    )
}

//or as a function
function provider () {
  return {
    thing: "one",
    anotherThing: 2
  }
}

render() {
    return (
        <Provider provide={provider}>
            {(function () {
                return <Anything>
            })}
        </Provider>
    )
}

• decorate a child component with inject and provide a mapping function determine which provided props to inject into the decorated component

var SomeChild = require('./SomeChildOfAnything') //a react Component

function mapProvidedToProps(provided) {
    return {
        that: provided.thing
    }
}

//notice that inject returns a wrapping function
var InjectedChild = inject(mapProvidedToProps)(SomeChild); 

// now in InjectedChild props will have `that`
...
render() {
    var injectedProp = this.props.that;
    return <span>{injectedProp}</span>;
    //will render as <span>one</span>
}

Best Practices

react-tunnel uses React's context feature to make provided props available to children regardless of how deep they are. While this is powerful it also can be abused and make for a nightmare to manage.

It is reccommended that this functionality be used to provide generally static properties that don't change much if at all based on the local conditions of the injecting component. Examples might include

• Providing viewport dimensions to arbitrarily deep Components
• Providing (redux)[https://github.com/rackt/redux] action creators from a parent connected Component to deep children

Also please consider that the context api for React has PropType checking for a reason and that by using this library and opting out of that stronger contract has costs and you may want to utilize the base context features rather than this library

API

<Provider provide>

makes provide available via context.provided to children of Provider. use inject to access them easily

Props

• provide {fn | object}:
  • provide: function(parentProvided) { return provided<object> }: will provide the return value of provide prop. Function takes in any provided values from parent providers if any. If none, an empty object is passed.
  • provide: object: provides any parent provided values if nested along with provide object properties. if there is a key collision the properties of the provide prop are used and mask similarly named properties from any parent provided objects

Children

until React 0.14 is realeased and the changes to parent context are implemented the only child Provider can have is a function. It should return what you want rendered inside the provider.

Nesting

Providers are nestable and if using the object version of provide will automatically reprovide any values provided in the immediate parent Provider. Use this if you want to say Provide some truly global props at the root of your App but also use Providers for (Redux action creators)[https://github.com/gaearon/react-redux] produced via connect to the local render tree.

If you nest Providers but use the function form of provide you will need to forward any desired parent provided values using the function forms argument parentProvided.

inject([mapProvidedToProps])

Creates a decorator which injects props from Provider into the decorated component according to the mapProvidedToProps function.

Arguments

• mapProvidedToProps(provided)? returns Object: called when decorated Component mounts and when it receives new context. the return object of this call is added to the underlying Component as props
• default: if mapProvidedToProps is not passed to ginject then all Provider values are passed to underlying component.

Thanks

• @gaearon for inspiring this API with the more specialized react-redux
• @rt2zz for helping flesh out the design and API

License

MIT