Fixed component double rendering in StrictMode

[psmyrek]

Suggested merge commit message (convention)

Fix: Fixed component double rendering in StrictMode. Closes #294.

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Additional information

It looks like this issue exists only in React v18+. React strict mode checks are run in development mode only. They do not impact the production build. For testing purposes we can use the sample/index.html.

1. Checkout the i/294 branch, bump React version in package.json for react and react-dom to ^18.0.0 and install dependencies.

2. Load the development builds for React framework in the sample/index.html:

   - <script src="../node_modules/react/umd/react.production.min.js"></script>
   - <script src="../node_modules/react-dom/umd/react-dom.production.min.js"></script>
   + <script src="../node_modules/react/umd/react.development.js"></script>
   + <script src="../node_modules/react-dom/umd/react-dom.development.js"></script>

3. Wrap the sample application in the <React.StrictMode>. Also, you need to change the way how the component is rendered in the sample/index.html (as the ReactDOM.render() is no longer supported in React v18):

   - document.addEventListener( 'DOMContentLoaded', () => {
   -     ReactDOM.render(
   -         React.createElement( App ),
   -         document.getElementById( 'root' )
   -     );
   - } );
   + document.addEventListener( 'DOMContentLoaded', () => {
   +     ReactDOM
   +         .createRoot( document.getElementById( 'root' ) )
   +         .render( React.createElement( React.StrictMode, null, React.createElement( App ) ) );
   + } );

4. Build the component: yarn run develop.

5. Open the sample and make sure it is rendered only once. There should be no warnings or errors in the console. If you have React Developer Tools installed in your browser, in the Components tab there should be no red exclamation sign indicating that the app is not in strict mode (because it is).

[coveralls]

Pull Request Test Coverage Report for Build 423

• 14 of 14 (100.0%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 100.0%

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Totals
Change from base Build 418:	0.0%
Covered Lines:	183
Relevant Lines:	183

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💛 - Coveralls