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    mini-create-react-context
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    0.4.1 • Public • Published

    mini-create-react-context

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    (A smaller) Polyfill for the React context API

    Install

    npm install mini-create-react-context

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

    API

    const Context = createReactContext(defaultValue);
    /*
        <Context.Provider value={providedValue}>
            {children}
        </Context.Provider>
     
        ...
     
        <Context.Consumer>
            {value => children}
        </Context.Consumer>
    */

    Example

    // @flow
    import React, { type Node } from 'react';
    import createReactContext, { type Context } from 'mini-create-react-context';
     
    type Theme = 'light' | 'dark';
    // Pass a default theme to ensure type correctness
    const ThemeContext: Context<Theme= 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)
          <ThemeContext.Provider value={this.state.theme}>
            <button
              onClick={() => {
                this.setState(state => ({
                  theme: state.theme === 'light' ? 'dark' : 'light'
                }));
              }}
            >
              Toggle theme
            </button>
            {this.props.children}
          </ThemeContext.Provider>
        );
      }
    }
     
    class Title extends React.Component<{ children: Node }> {
      render() {
        return (
          // The Consumer uses a render prop API. Avoids conflicts in the
          // props namespace.
          <ThemeContext.Consumer>
            {theme => (
              <h1 style={{ color: theme === 'light' ? '#000' : '#fff' }}>
                {this.props.children}
              </h1>
            )}
          </ThemeContext.Consumer>
        );
      }
    }

    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:

    <Context.Provider>
      <div/>
      <div/>
    </Context.Provider>

    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 <Context.Provider> can only receive a single child element. To fix the error just wrap everyting in a single <div>:

    <Context.Provider>
      <div>
        <div/>
        <div/>
      </div>
    </Context.Provider>

    Size difference to the original:

    original mini
    install size 50 kB 140 kB
    minified 3.3 kB 2.3kB
    minzip 1.3 kB 1.0kB

    Install

    npm i mini-create-react-context

    DownloadsWeekly Downloads

    3,224,494

    Version

    0.4.1

    License

    MIT

    Unpacked Size

    19.7 kB

    Total Files

    7

    Last publish

    Collaborators

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