javascript - 如何将 React 组件导出为 npm 包？创建 react 应用语法错误 : Unexpected token

Question

我创建了名为“create-react-app-npm”的 React 应用程序。在 ./src/index.js 文件中，我导出了组件以在另一个项目中使用它的 npm 包。首先，我在我的主根中运行了这段代码。

npm run eject 然后是我项目的下一部分

这是create-react-app-npm文件夹下的src/index.js

import React from 'react';
import './index.css';
import App from './App';

class ExportApp extends React.Component{
    render(){
        return(<App sayHi="hello There I am creating my first npm package"/>);
    }
}
export default ExportApp;

这是create-react-app-npm文件夹下的package.json文件

{
  "name": "create-react-app-npm",
  "version": "0.1.0",
  "main": "src/index.js",
  "dependencies": {
    "@babel/core": "7.5.5",
    "@svgr/webpack": "4.3.2",
    "@typescript-eslint/eslint-plugin": "1.13.0",
    "@typescript-eslint/parser": "1.13.0",
    "babel-eslint": "10.0.2",
    "babel-jest": "^24.8.0",
    "babel-loader": "8.0.6",
    "babel-plugin-named-asset-import": "^0.3.3",
    "babel-preset-react-app": "^9.0.1",
    "camelcase": "^5.2.0",
    "case-sensitive-paths-webpack-plugin": "2.2.0",
    "css-loader": "2.1.1",
    "dotenv": "6.2.0",
    "dotenv-expand": "4.2.0",
    "eslint": "^6.1.0",
    "eslint-config-react-app": "^5.0.1",
    "eslint-loader": "2.2.1",
    "eslint-plugin-flowtype": "3.13.0",
    "eslint-plugin-import": "2.18.2",
    "eslint-plugin-jsx-a11y": "6.2.3",
    "eslint-plugin-react": "7.14.3",
    "eslint-plugin-react-hooks": "^1.6.1",
    "file-loader": "3.0.1",
    "fs-extra": "7.0.1",
    "html-webpack-plugin": "4.0.0-beta.5",
    "identity-obj-proxy": "3.0.0",
    "is-wsl": "^1.1.0",
    "jest": "24.8.0",
    "jest-environment-jsdom-fourteen": "0.1.0",
    "jest-resolve": "24.8.0",
    "jest-watch-typeahead": "0.3.1",
    "mini-css-extract-plugin": "0.5.0",
    "optimize-css-assets-webpack-plugin": "5.0.3",
    "pnp-webpack-plugin": "1.5.0",
    "postcss-flexbugs-fixes": "4.1.0",
    "postcss-loader": "3.0.0",
    "postcss-normalize": "7.0.1",
    "postcss-preset-env": "6.7.0",
    "postcss-safe-parser": "4.0.1",
    "react": "^16.9.0",
    "react-app-polyfill": "^1.0.2",
    "react-dev-utils": "^9.0.3",
    "react-dom": "^16.9.0",
    "resolve": "1.12.0",
    "resolve-url-loader": "3.1.0",
    "sass-loader": "7.2.0",
    "semver": "6.3.0",
    "style-loader": "1.0.0",
    "terser-webpack-plugin": "1.4.1",
    "ts-pnp": "1.1.2",
    "url-loader": "2.1.0",
    "webpack": "4.39.1",
    "webpack-dev-server": "3.2.1",
    "webpack-manifest-plugin": "2.0.4",
    "workbox-webpack-plugin": "4.3.1"
  },
  "scripts": {
    "start": "node scripts/start.js",
    "build": "node scripts/build.js",
    "test": "node scripts/test.js"
  },
  "eslintConfig": {
    "extends": "react-app"
  },
  "browserslist": {
    "production": [
      ">0.2%",
      "not dead",
      "not op_mini all"
    ],
    "development": [
      "last 1 chrome version",
      "last 1 firefox version",
      "last 1 safari version"
    ]
  },
  "jest": {
    "roots": [
      "<rootDir>/src"
    ],
    "collectCoverageFrom": [
      "src/**/*.{js,jsx,ts,tsx}",
      "!src/**/*.d.ts"
    ],
    "setupFiles": [
      "react-app-polyfill/jsdom"
    ],
    "setupFilesAfterEnv": [],
    "testMatch": [
      "<rootDir>/src/**/__tests__/**/*.{js,jsx,ts,tsx}",
      "<rootDir>/src/**/*.{spec,test}.{js,jsx,ts,tsx}"
    ],
    "testEnvironment": "jest-environment-jsdom-fourteen",
    "transform": {
      "^.+\\.(js|jsx|ts|tsx)$": "<rootDir>/node_modules/babel-jest",
      "^.+\\.css$": "<rootDir>/config/jest/cssTransform.js",
      "^(?!.*\\.(js|jsx|ts|tsx|css|json)$)": "<rootDir>/config/jest/fileTransform.js"
    },
    "transformIgnorePatterns": [
      "[/\\\\]node_modules[/\\\\].+\\.(js|jsx|ts|tsx)$",
      "^.+\\.module\\.(css|sass|scss)$"
    ],
    "modulePaths": [],
    "moduleNameMapper": {
      "^react-native$": "react-native-web",
      "^.+\\.module\\.(css|sass|scss)$": "identity-obj-proxy"
    },
    "moduleFileExtensions": [
      "web.js",
      "js",
      "web.ts",
      "ts",
      "web.tsx",
      "tsx",
      "json",
      "web.jsx",
      "jsx",
      "node"
    ],
    "watchPlugins": [
      "jest-watch-typeahead/filename",
      "jest-watch-typeahead/testname"
    ]
  },
  "babel": {
    "presets": [
      "react-app"
    ]
  },
  "devDependencies": {
    "babel-cli": "^6.26.0",
    "babel-preset-es2015": "^6.24.1",
    "babel-preset-react": "^6.24.1",
    "babel-preset-stage-0": "^6.24.1"
  }
}

当我在项目的根文件夹中时，我在终端中运行了 npm link。

创建这个主项目后，我还使用 create-react-app npm_test 代码创建了 npm_test 项目文件夹。

我已经运行了 npm link create-react-app-npm 代码来链接之前的 main project which is create-react-app-npm 和我的第二个 npm-test项目。

我的 App.js 文件在我的 npm-test 项目文件夹中。

import React from 'react';
import './App.css';
import ExportApp from 'create-react-app-npm'

function App2() {
  return (
    <div className="App">
     <ExportApp/>
    </div>
  );
}

export default App2;

当我运行 npm start 时，我无法运行该项目。我收到了错误消息。我不知道这是什么意思。我该怎么办？

错误是这样的

Failed to compile.

../create-react-app-npm/src/index.js
SyntaxError: /home/semih/Desktop/create-react-app-npm/src/index.js: Unexpected token (7:15)

   5 | class ExportApp extends React.Component{
   6 |     render(){
>  7 |         return(<App sayHi="hello There I am creating my first npm package"/>);
     |                ^
   8 |     }
   9 | }
  10 | export default ExportApp;

我希望在 npm-test 项目中运行 ExportMain 组件。我应该走什么样的路？

Answer 1

Create React App/CRA 不是构建和捆绑 npm 包的最佳工具，它的 main purpose是创建单页应用程序。对于组件库，CRA 团队 recommends使用 more flexible toolchains .

因为你已经弹出了 CRA，你仍然可以尝试调整 Webpack 配置。这是一个示例配置，其中包含针对 npm 包的基本设置:

// simply way to exclude all node_modules from bundle.
// You can configure entries manually, too.
const nodeExternals = require('webpack-node-externals');

module.exports = {
  ...
  output: {
    // provide entry point exports via CommonJS / as npm package
    libraryTarget: "commonjs"
  },
  ...
  // ignore built-in modules like path, fs, etc.
  target: "node",
  // don't bundle node_modules with your library
  // external packages should be required
  externals: [nodeExternals()]
};

关于 CRA，将这些设置添加到基本配置中 <root>/config/webpack.config.js .可能的进一步调整:

output: {
  // give your main npm package file a static name
  // It should be stored to build/node_bundle.js
  filename: "node_bundle.js"
},

package.json:

"main": "build/node_bundle.js"

最后，构建您的库并在您的客户端应用程序中需要它。

链接:

• Webpack libraryTarget设置
• Webpack externals设置
• webpack-node-externals
• Authoring libraries