Webpack 无法在简单项目中使用 npm start
2019-05-26
1307
这是我的包文件和 webpack 配置。我正在学习这项技术,但这不起作用。我在一个空白画布项目中收到以下错误。我做错了什么吗?
非常感谢,
错误消息
ERROR in ./src/index.js 6:16
Module parse failed: Unexpected token (6:16)
You may need an appropriate loader to handle this file type.
| import App from './App';
|
> ReactDOM.render(<App />, document.getElementById('root'));
package.json
{
"name": "boilerplate",
"version": "1.0.0",
"description": "",
"main": "index.js",
"scripts": {
"start": "webpack --mode development --watch",
"build": "webpack --mode production"
},
"keywords": [],
"author": "",
"license": "ISC",
"devDependencies": {
"babel-core": "^6.26.3",
"babel-loader": "^8.0.6",
"babel-preset-env": "^1.7.0",
"babel-preset-react": "^6.24.1",
"css-loader": "^2.1.1",
"html-webpack-plugin": "^3.2.0",
"style-loader": "^0.23.1",
"webpack": "^4.32.2",
"webpack-cli": "^3.3.2"
},
"dependencies": {
"react": "^16.8.6",
"react-dom": "^16.8.6"
}
}
webpack.config.js
var HtmlWebpackPlugin = require('html-webpack-plugin');
var path = require('path');
module.exports = {
entry: './src/index.js',
output: {
path: path.join(__dirname, './dist'),
filename: 'index_bundle.js'
},
plugins: [new HtmlWebpackPlugin()]
};
App.js
import React, { Component } from 'react';
class App extends Component {
render() {
return (
<div>
<h1>hello</h1>
</div>
)
}
}
我现在有以下 webpack.config.js
更新 - 完整文件
var HtmlWebpackPlugin = require('html-webpack-plugin');
var path = require('path');
module.exports = {
entry: './src/index.js',
output: {
path: path.join(__dirname, './dist'),
filename: 'index_bundle.js'
},
resolve: {
extensions: ['', '.js', '.jsx']
},
module: {
loaders: [
{
test: /\.jsx?$/,
loader: 'babel',
exclude: /node_modules/,
query: {
cacheDirectory: true,
presets: ['react', 'es2015']
}
}
]
},
plugins: [new HtmlWebpackPlugin()]
};
进行此更改后,在运行 npm install 后,运行 npm start 时出现以下错误
Invalid configuration object. Webpack has been initialised using a configuration object that does not match the API schema.
- configuration.module has an unknown property 'loaders'. These properties are valid:
object { defaultRules?, exprContextCritical?, exprContextRecursive?, exprContextRegExp?, exprContextRequest?, noParse?, rules?, strictExportPrese
nce?, strictThisContextOnImports?, unknownContextCritical?, unknownContextRecursive?, unknownContextRegExp?, unknownContextRequest?, unsafeCache?, w
rappedContextCritical?, wrappedContextRecursive?, wrappedContextRegExp? }
-> Options affecting the normal modules (`NormalModuleFactory`).
- configuration.resolve.extensions[0] should be an non-empty string.
-> A non-empty string
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! [email protected] start: `webpack --mode development --watch`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the [email protected] start script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
更新 2
var HtmlWebpackPlugin = require('html-webpack-plugin');
var path = require('path');
module.exports = {
entry: './src/index.js',
output: {
path: path.join(__dirname, './dist'),
filename: 'index_bundle.js'
},
resolve: {
extensions: ['.js', '.jsx']
},
module: {
rules: [
{
test: /\.js$/,
exclude: /node_modules/,
use: {
loader: "babel-loader"
}
}
]
},
plugins: [new HtmlWebpackPlugin()]
};
此版本的
文件
[./src/index.js] 3.16 KiB {main} [not cacheable] [built] [failed] [1 error]
ERROR in ./src/index.js
Module build failed (from ./node_modules/babel-loader/lib/index.js):
Error: Cannot find module '@babel/core'
babel-loader@8 requires Babel 7.x (the package '@babel/core'). If you'd like to use Babel 6.x ('babel-core'), you should install 'babel-loader@7'.
at Function.Module._resolveFilename (internal/modules/cjs/loader.js:613:15)
2个回答
将其添加到您的 webpack 中 ...您的 webpack 中的代码...
,resolve: {
extensions: ['', '.js', '.jsx']
},
module: {
loaders: [
{
test: /\.jsx?$/,
loader: 'babel',
exclude: /node_modules/,
query: {
cacheDirectory: true,
presets: ['react', 'es2015']
}
}
]
}
在您的文件夹中尝试
npm install
,然后再次使用
npm start
evilGenius
2019-05-26
首先,您的属性
module:{
loaders
不正确,应该是 modules->rules 。其次,您的文件夹中没有任何 JSX,您有 App.js,因此您的规则应该对其进行测试并为其加载适当的加载器,即 babel-loader,其预设设置为 react
module: {
rules: [
{
test: /\.js$/,
exclude: /node_modules/,
use: {
loader: "babel-loader"
}
}
要告诉 babel 使用 react 作为其预设,您可以在上述配置中指定或创建一个包含以下内容的 .babelrc 文件。
{
"presets": ["@babel/preset-env", "@babel/preset-react"]
}
之后,您就可以开始了
Avij
2019-05-27