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2022年12月になってもcreate-react-appでReact 17を新規作成したい

· 約3分
moritalous

Reactプロジェクトの作成​

まずはcreate-react-appを実行します。

npx create-react-app app --template typescript

React 18で作成されます。

package.json
{
  "name": "app",
  "version": "0.1.0",
  "private": true,
  "dependencies": {
    "@testing-library/jest-dom": "^5.16.5",
    "@testing-library/react": "^13.4.0",
    "@testing-library/user-event": "^13.5.0",
    "@types/jest": "^27.5.2",
    "@types/node": "^16.18.6",
    "@types/react": "^18.0.26",
    "@types/react-dom": "^18.0.9",
    "react": "^18.2.0",
    "react-dom": "^18.2.0",
    "react-scripts": "5.0.1",
    "typescript": "^4.9.3",
    "web-vitals": "^2.1.4"
  },
  "scripts": {
    "start": "react-scripts start",
    "build": "react-scripts build",
    "test": "react-scripts test",
    "eject": "react-scripts eject"
  },
  "eslintConfig": {
    "extends": [
      "react-app",
      "react-app/jest"
    ]
  },
  "browserslist": {
    "production": [
      ">0.2%",
      "not dead",
      "not op_mini all"
    ],
    "development": [
      "last 1 chrome version",
      "last 1 firefox version",
      "last 1 safari version"
    ]
  }
}

React 17にダウングレード​

  1. package.jsonのdependenciesを修正します。

       "dependencies": {
         "@testing-library/jest-dom": "^5.16.5",
    -    "@testing-library/react": "^13.4.0",
    +    "@testing-library/react": "^12.0.0",
         "@testing-library/user-event": "^13.5.0",
         "@types/jest": "^27.5.2",
         "@types/node": "^16.18.6",
    -    "@types/react": "^18.0.26",
    -    "@types/react-dom": "^18.0.9",
    -    "react": "^18.2.0",
    -    "react-dom": "^18.2.0",
    +    "@types/react": "^17.0.0",
    +    "@types/react-dom": "^17.0.0",
    +    "react": "^17.0.0",
    +    "react-dom": "^17.0.0",
         "react-scripts": "5.0.1",
         "typescript": "^4.9.3",
         "web-vitals": "^2.1.4"
       },

  2. パッケージを再インストール

    cd app
    rm -rf node_modules
    npm i

  3. index.tsxを修正

    修正前
    import React from 'react';
    import ReactDOM from 'react-dom/client';
    import './index.css';
    import App from './App';
    import reportWebVitals from './reportWebVitals';

    const root = ReactDOM.createRoot(
      document.getElementById('root') as HTMLElement
    );
    root.render(
      <React.StrictMode>
        <App />
      </React.StrictMode>
    );

    // If you want to start measuring performance in your app, pass a function
    // to log results (for example: reportWebVitals(console.log))
    // or send to an analytics endpoint. Learn more: https://bit.ly/CRA-vitals
    reportWebVitals();
    修正後
    import React from 'react';
    import ReactDOM from 'react-dom';
    import './index.css';
    import App from './App';
    import reportWebVitals from './reportWebVitals';

    const root = document.getElementById('root');

    ReactDOM.render(
      <React.StrictMode>
        <App />
      </React.StrictMode>,
      root
    );

    // If you want to start measuring performance in your app, pass a function
    // to log results (for example: reportWebVitals(console.log))
    // or send to an analytics endpoint. Learn more: https://bit.ly/CRA-vitals
    reportWebVitals();

以上で完成です。

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