TypeError：（0，_react.useEffect）不是一个函数

在开发环境中时，我的应用程序可以正常工作。在生产环境中时，它崩溃并显示以下错误：

Uncaught TypeError: (0 , _react.useEffect) is not a function

这发生在我导入React和useEffect的文件中，如下所示：

import React, { useEffect } from 'react'

const X = () => {
  useEffect(() => { ... })

  ...
}

在此行下添加console.log确认在生产中useEffect确实是未定义的，在dev中则是预期的功能。

我检查了package.json，yarn.lock和node_modules中是否存在引入了useEffect的16.8.0以下的任何react或react-dom版本。但是所有内容都是16.13.1，它们是主要依赖项，我确实尝试清理了纱线缓存，删除了node_modules＆yarn.lock，然后重新安装。

我尝试将其添加和删除peerDependencies失败。

我检查一下以确保没有运行两个独立版本的React，但要保存window.React1 = React在库和window.React2 = React我的应用程序中并检查

window.React1 === window.React2 是真的，所以也不是。

最后，我还尝试将React别名为node_modules中的特定别名，但是没有任何运气。

我发现可行的唯一解决方案是按如下方式导入它：

import React from 'react';

const X = () => {
  React.useEffect(() => { ... })
  ...
}

但这应该与使用非结构化导入完全相同吗？如果我确实明确使用React.useEffect，它也会迫使我将所有其他useState和useEffect钩子更改为React.useSate和React.useEffect

下一个错误就变成：TypeError: (0 , _react.useState) is not a function在另一个我使用React钩子的文件中。

我想解决不实施解决方法的问题。

我曾经使用microbundleReact将我的图书馆捆绑在一起。我parcel-bundler用来导入React组件并将其呈现在开发环境（直接从src）或prod（捆绑的库）中

我使用的捆绑版本与.mjs捆绑在一起

我也检查了缩小的.mjs包的输出，并在React中像这样导入：

import ue,{useEffect as pe,useState as fe}from"react";

在我看来，这很好。

我真正不明白的是重组的导入将如何破坏它，但是仅仅执行React.useEffect就可以了吗？

这是我的package.json

{
  "name": "xxx",
  "version": "1.1.4",
  "repository": "git@github.com:xxx/xxx.git",
  "author": "xxx",
  "license": "MIT",
  "source": "src/index.ts",
  "main": "dist/bundle.js",
  "umd:main": "dist/bundle.umd.js",
  "module": "dist/bundle.mjs",
  "publishConfig": {
    "registry": "https://npm.pkg.github.com/@xxx"
  },
  "scripts": {
    "build": "microbundle",
    "dev": "parcel ./test-app/dev/index.html --port 3000",
    "start": "parcel ./test-app/serve/index.html --port 3000",
    "storybook": "start-storybook -s ./public -c .storybook --ci",
    "prepublishOnly": "yarn build"
  },
  "dependencies": {
    "@api-platform/admin": "2.1.0",
    "@api-platform/api-doc-parser": "0.8.2",
    "@fortawesome/fontawesome-svg-core": "^1.2.28",
    "@fortawesome/free-solid-svg-icons": "^5.13.0",
    "@fortawesome/react-fontawesome": "^0.1.9",
    "@material-ui/core": "^4.9.10",
    "@material-ui/icons": "^4.9.1",
    "@react-keycloak/web": "^2.1.1",
    "@types/pluralize": "^0.0.29",
    "google-geocoder": "0.2.1",
    "history": "^4.10.1",
    "keycloak-js": "^9.0.3",
    "lodash.debounce": "^4.0.8",
    "lodash.omit": "^4.5.0",
    "lodash.set": "4.3.2",
    "notistack": "0.9.9",
    "papaparse": "^5.2.0",
    "parcel-bundler": "1.12.4",
    "polished": "^3.5.2",
    "react": "16.13.1",
    "react-admin": "3.4.1",
    "react-dom": "16.13.1",
    "react-is": "16.13.1",
    "react-redux": "^7.2.0",
    "recompose": "^0.30.0",
    "redux": "4.0.5",
    "styled-components": "5.1.0"
  },
  "devDependencies": {
    "@babel/core": "7.9.0",
    "@babel/plugin-syntax-export-default-from": "7.8.3",
    "@babel/preset-env": "7.9.5",
    "@babel/preset-react": "7.9.4",
    "@storybook/addon-a11y": "5.3.18",
    "@storybook/addon-actions": "5.3.18",
    "@storybook/addon-info": "5.3.18",
    "@storybook/addon-knobs": "5.3.18",
    "@storybook/addon-links": "5.3.18",
    "@storybook/addon-storyshots": "5.3.18",
    "@storybook/addon-storysource": "5.3.18",
    "@storybook/addon-viewport": "5.3.18",
    "@storybook/react": "5.3.18",
    "@testing-library/react": "^10.0.3",
    "@types/jsonld": "1.5.1",
    "@types/lodash": "4.14.149",
    "@types/node": "13.11.1",
    "@types/papaparse": "5.0.3",
    "@types/react-redux": "7.1.7",
    "@types/recompose": "^0.30.7",
    "@types/styled-components": "5.1.0",
    "@welldone-software/why-did-you-render": "4.0.7",
    "awesome-typescript-loader": "5.2.1",
    "babel-loader": "^8.1.0",
    "babel-plugin-module-resolver": "4.0.0",
    "babel-plugin-styled-components": "1.10.7",
    "lodash.get": "4.4.2",
    "lodash.uniq": "4.5.0",
    "microbundle": "0.11.0",
    "openapi-types": "1.3.5",
    "parcel-plugin-static-files-copy": "2.3.1",
    "pluralize": "^8.0.0"
  },
  "alias": {
    "jsonld": "./node_modules/jsonld/dist/jsonld.js"
  },
  "staticFiles": {
    "staticPath": "public",
    "watcherGlob": "**"
  }
}

同样值得注意的是，这只是React我遇到的问题。我所有其他经过重组的进口商品都可以正常工作。

似乎microbundler不能容忍React。这个创建包试图react从全局范围使用，而不是React真正公开。

出于同样的原因，您的解决方法也React.useEffect可以按预期工作，请想象它看起来像window.React.useEffect。

这是原始应用程序的示例：

import ReactDOM from 'react-dom';
import React, { useEffect, useState } from 'react';

/**
 * necessary workaround, microbundle use `h` pragma by default,
 * that undefined when use React
 * another option is to make build with option --jsx
 * @example microbundle --globals react=React --jsx React.createElement
 * yes, yet another workaround
*/
window.h = React.createElement;

const X = () => {
  const [A, B] = useState('world');

  useEffect(() => {
    B('MLyck');
  }, [])

  return `Hello ${A}`;
}

ReactDOM.render(<X />, document.querySelector('react-app'));

捆绑在一起后，microbundle它完全破裂了，但是当您尝试捆绑时

microbundle --globals react=React

正确建议@Jee Mok，它将产生正确的捆绑包。我希望评论能解释发生了什么。

!function (e, t) {
  "object" == typeof exports && "undefined" != typeof module ?
    t(require("react-dom"), require("react")) :
    "function" == typeof define && define.amd ?
      define(["react-dom", "react"], t) :
      t(e.ReactDOM, e.React);
  /*
  String above is core of problem,
  in case you try to bundle without options `--globals react=React`
  it will looks like: `t(e.ReactDOM, e.react);`
  Obviously `react` is not defined in `e` e.g. `this` e.g. `window`
  due to react expose self as `React`
   */
}(this, function (e, t) {
  e = e && e.hasOwnProperty("default") ? e.default : e, window.h = ("default" in t ? t.default : t).createElement, e.render(h(function () {
    var e = t.useState("world"), n = e[0], r = e[1];
    return t.useEffect(function () {
      r("MLyck");
    }, []), "Hello " + n;
  }, null), document.querySelector("react-app"));
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.13.1/umd/react.development.js"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.13.1/umd/react-dom.development.js"></script>

    <react-app></react-app>

而且，顺便说一句，“重组进口”一点也不怪。