create-react-context

> Polyfill for the proposed React context API

Install

yarn add create-react-context

You'll need to also have react and prop-types installed.

API

const Context = createReactContext(defaultValue);
// {children}
// ...
// {value => children}

Example

// @flow
import React, { type Node } from 'react';
import createReactContext, { type Context } from 'create-react-context';

type Theme = 'light' | 'dark';
// Pass a default theme to ensure type correctness
const ThemeContext: Context = createReactContext('light');

class ThemeToggler extends React.Component<
  { children: Node },
  { theme: Theme }
> {
  state = { theme: 'light' };
  render() {
    return (
      // Pass the current context value to the Provider's `value` prop.
      // Changes are detected using strict comparison (Object.is)
      
        <button> {
            this.setState(state =&gt; ({
              theme: state.theme === 'light' ? 'dark' : 'light'
            }));
          }}
        &gt;
          Toggle theme
        </button>
        {this.props.children}
      
    );
  }
}

class Title extends React.Component&lt;{ children: Node }&gt; {
  render() {
    return (
      // The Consumer uses a render prop API. Avoids conflicts in the
      // props namespace.
      
        {theme =&gt; (
          <h1 style="{{">
            {this.props.children}
          </h1>
        )}
      
    );
  }
}

Compatibility

This package only "ponyfills" the React.createContext API, not other unrelated React 16+ APIs. If you are using a version of React <16, keep in mind that you can only use features available in that version.

For example, you cannot pass children types aren't valid pre React 16:

  <div>
  <div>

It will throw A valid React element (or null) must be returned. You may have returned undefined, an array or some other invalid object. because `` can only receive a single child element. To fix the error just wrap everyting in a single <div>:

  <div>
    <div>
    <div>
  </div>

```</div></div></div></div></div>