https://github.com/jaykan/react-multiple-renderers-error

A demo repo to demonstrate multiple renderers error working with Context API
https://github.com/jaykan/react-multiple-renderers-error

Last synced: 3 months ago
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A demo repo to demonstrate multiple renderers error working with Context API

• Host: GitHub
• URL: https://github.com/jaykan/react-multiple-renderers-error
• Owner: JayKan
• Created: 2018-07-09T07:22:23.000Z (over 7 years ago)
• Default Branch: master
• Last Pushed: 2018-07-09T07:34:32.000Z (over 7 years ago)
• Last Synced: 2025-07-03T09:45:50.053Z (6 months ago)
• Language: JavaScript
• Size: 194 KB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

          
# ReactDOM.render() + React.createContext() Multiple Renderers Error

> Warning: Detected multiple renderers concurrently rendering the same context provider. This is currently unsupported.

The above warning occurs __only__ when you have `ReactDOM.render()` and `TestRenderer` (react-test-renderer) coexists within your test file. For instance: 

```javascript 

// This is my actual App.test.js file 

describe('App', () => {

  it('renders without crashing', () => {

    const div = document.createElement('div');

    ReactDOM.render(, div); // comment out this line to get rid of errors

    ReactDOM.unmountComponentAtNode(div); // no need to comment out this one

  });

  describe('#react-test-renderer working with React.render() :(', () => {

    const makeComponent = props => TestRenderer.create();

    it('started to fail', () => {

      const component = makeComponent({ level: 1, maxLevel: 20 });

      const instance = component.getInstance();

      expect(instance.state.level).toBe(1);

      expect(instance.state.maxLevel).toBe(20);

    });

  });

});

// When you `npm t` or `yarn test`, you will get a warning from above

// However, if you comment out ReactDOM.render(, div) line, warning disappears 

```