我正在尝试运行非常简单的代码,但出现错误,我没有使用 create react 应用程序!
看起来我的 babel.config.js 文件被忽略了!
我的 html 文件
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>ReactJS</title>
</head>
<body>
<div id="app"></div>
<script src = 'bundle.js' ></script>
</body>
</html>
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我的 index.js 文件:
import React from 'react';
import { render } from 'react-dom';
render(<h1>Hello World!!</h1>, document.getElementById('app'));
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我的包json:
{
"name": "front",
"version": "1.0.0",
"main": "index.js",
"license": "MIT",
"scripts": {
"dev": "webpack-dev-server --mode development",
"build": "webpack-dev-server --mode production"
},
"dependencies": {
"@babel/cli": "^7.10.5",
"@babel/core": "^7.10.5",
"@babel/plugin-proposal-class-properties": "^7.10.4",
"@babel/preset-env": …Run Code Online (Sandbox Code Playgroud) 我开始写新的使用玩笑和酶反应的应用程序,当尝试使用笑话一样运行测试用例的单元测试用例"test": "jest --watch",而"test": "react-scripts test"测试通过巴贝尔去获得亚军,了解反应的语法。
并且一直在使用 babel 一步一步地进行设置,但是这个错误Support for the experimental syntax 'jsx' isn't currently enabled阻止了我走得更远。正如我在一些线程中所建议的那样,我一直在尝试npm install --save-dev @babel/plugin-transform-react-jsx并尝试将相同的插件添加到 babel 配置中,如下面的 package.json 文件所示,但仍然没有运气。

这是我的 package.json
{
"name": "multitheme-app",
"version": "0.1.0",
"private": true,
"dependencies": {
"@material-ui/core": "^3.9.0",
"@material-ui/icons": "^3.0.2",
"axios": "^0.18.0",
"babel-plugin-transform-export-extensions": "^6.22.0",
"jest-css-modules": "^2.1.0",
"react": "^16.8.1",
"react-dom": "^16.8.1",
"react-redux": "^6.0.0",
"react-router-dom": "^4.3.1",
"react-scripts": "2.1.5",
"redux": "^4.0.1",
"redux-thunk": "^2.3.0"
},
"scripts": {
"start": "react-scripts start",
"build": "react-scripts build",
"test": "react-scripts test",
"eject": "react-scripts …Run Code Online (Sandbox Code Playgroud) 我是reactjs新手。我读过类似的错误帖子,语法错误:当前未启用对实验性语法“jsx”的支持 ,但无法解决我的问题
当我跑步时npm run dev
我有一个错误
ERROR in ./src/index.js
Module build failed (from ./node_modules/babel-loader/lib/index.js):
SyntaxError: -..../frontend/src/index.js: Support for the experimental syntax 'jsx' isn't currently enabled (40:7):
38 | render() {
39 | return (
> 40 | <ul>
| ^
41 | {this.state.data.map(contact => {
42 | return (
43 | <li key={contact.id}>
Add @babel/preset-react (https://git.io/JfeDR) to the 'presets' section of your Babel config to enable transformation.
If you want to leave it as-is, add @babel/plugin-syntax-jsx (https://git.io/vb4yA) to …Run Code Online (Sandbox Code Playgroud) 我对React.js非常陌生。我安装了Laravel 5.7并通过运行以下命令将Vue.js支架与React交换:
php artisan preset react
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现在的问题是,我无法为组件内部的状态分配任何内容。
例如,如果我在组件内执行以下操作:
state = { foo: false };
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我得到了错误:
ERROR in ./resources/js/components/Root.js
Module build failed (from ./node_modules/babel-loader/lib/index.js):
SyntaxError: D:\xampp\htdocs\smart-school-v0.1\resources\js\components\Root.js: Support for the experimental syntax 'classProperties' isn't currently enabled (8:11):
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我安装了:
@babel/plugin-proposal-class-properties
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并更新.babelrc(Babel配置文件),如下所示:
{
"presets": [
"@babel/preset-env",
"@babel/preset-react"
],
"plugins": [
"@babel/plugin-proposal-class-properties"
]
}
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我遵循了这个,但是没有运气。
Package.json
{
"private": true,
"scripts": {
"dev": "npm run development",
"development": "cross-env NODE_ENV=development node_modules/webpack/bin/webpack.js --progress --hide-modules --config=node_modules/laravel-mix/setup/webpack.config.js",
"watch": "npm run …Run Code Online (Sandbox Code Playgroud) 我正在使用 npm 运行一个 React 项目。经过数小时的研究和试验,到处都说我必须将以下代码添加到我的“.babelrc”文件中,我的目录中没有并且无法创建:
{
"plugins": [
["@babel/plugin-proposal-class-properties", { "loose": true }]
]
}
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但是当我运行代码时,这会导致以下错误:
ERROR in ./src/components/NavBar/Menu.js
Module build failed (from ./node_modules/babel-loader/lib/index.js):
SyntaxError: /Users/ymoondhra/Desktop/yt-web/src/components/NavBar/Menu.js:
Support for the experimental syntax 'classProperties' isn't currently enabled
(20:10):
18 | }
19 |
> 20 | fast = () => {
| ^
21 | this.speed = 100;
22 | }
23 |
Add @babel/plugin-proposal-class-properties (https://git.io/vb4SL) to the 'plugins'
section of your Babel config to enable transformation.
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