我正在尝试使用 create-react-app 包和一个简单的组件库构建一个 lerna 包。我的组件如下:
import React, { Component } from "react";
import PropTypes from "prop-types";
class Layout extends Component {
render = () => {
let style = {
fontSize: 14,
fontFamily:
"-apple-system, system-ui, 'Segoe UI', Roboto, Oxygen-Sans, Ubuntu, Cantarell, 'Helvetica Neue', sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol', sans-serif",
fontWeight: 400
};
return <div style={style}>{this.props.children}</div>;
};
}
export default Layout;
我原来的create-react-app如下:
index.js
import React from 'react';
import ReactDOM from 'react-dom';
import App from './components/app/App/App';
ReactDOM.render(<App />, document.getElementById('root'));
App.js
import React, { Component } from "react";
import Layout from "@project/webux/lib/Layout";
class App extends Component {
render = () => {
return (
<Layout>
Hello!
</Layout>
);
};
}
export default App;
运行时，出现以下错误:
../webux/lib/Layout/index.js
SyntaxError: /Volumes/workspace/dev/packages/webux/lib/Layout/index.js: Support for the experimental syntax 'classProperties' isn't currently enabled (5:12):
3 |
4 | class Layout extends Component {
> 5 | render = () => {
| ^
6 | let style = {
7 | fontSize: 14,
8 | fontFamily:
Add @babel/plugin-proposal-class-properties (https://git.io/vb4SL) to the 'plugins' section of your Babel config to enable transformation.
发生此错误的原因是 create-react-app 不会在其项目之外转译文件。由于我的组件 Layout 驻留在另一个目录中的另一个 lerna 包中，因此它不会被转译。
为了解决这个问题，我弹出了 create-react-app 应用程序，并最终得到以下 webpack 配置文件，其中添加了 ==== INCLUDED=== 一段用于设置 input 目录的代码(我已在项目上方添加了该目录，因为这将指向我的lerna \packages 目录，因此所有包文件都会被处理:
...
resolve: {
// This allows you to set a fallback for where Webpack should look for modules.
// We placed these paths second because we want `node_modules` to "win"
// if there are any conflicts. This matches Node resolution mechanism.
// https://github.com/facebook/create-react-app/issues/253
modules: ['node_modules', paths.appNodeModules].concat(
modules.additionalModulePaths || []
),
// These are the reasonable defaults supported by the Node ecosystem.
// We also include JSX as a common component filename extension to support
// some tools, although we do not recommend using it, see:
// https://github.com/facebook/create-react-app/issues/290
// `web` extension prefixes have been added for better support
// for React Native Web.
extensions: paths.moduleFileExtensions
.map(ext => `.${ext}`)
.filter(ext => useTypeScript || !ext.includes('ts')),
alias: {
// Support React Native Web
// https://www.smashingmagazine.com/2016/08/a-glimpse-into-the-future-with-react-native-for-web/
'react-native': 'react-native-web',
// Allows for better profiling with ReactDevTools
...(isEnvProductionProfile && {
'react-dom$': 'react-dom/profiling',
'scheduler/tracing': 'scheduler/tracing-profiling',
}),
...(modules.webpackAliases || {}),
},
plugins: [
// Adds support for installing with Plug'n'Play, leading to faster installs and adding
// guards against forgotten dependencies and such.
PnpWebpackPlugin,
// Prevents users from importing files from outside of src/ (or node_modules/).
// This often causes confusion because we only process files within src/ with babel.
// To fix this, we prevent you from importing files out of src/ -- if you'd like to,
// please link the files into your node_modules/ and let module-resolution kick in.
// Make sure your source files are compiled, as they will not be processed in any way.
new ModuleScopePlugin(paths.appSrc, [paths.appPackageJson]),
],
},
resolveLoader: {
plugins: [
// Also related to Plug'n'Play, but this time it tells Webpack to load its loaders
// from the current package.
PnpWebpackPlugin.moduleLoader(module),
],
},
module: {
strictExportPresence: true,
rules: [
// Disable require.ensure as it's not a standard language feature.
{ parser: { requireEnsure: false } },
// First, run the linter.
// It's important to do this before Babel processes the JS.
{
test: /\.(js|mjs|jsx|ts|tsx)$/,
enforce: 'pre',
use: [
{
options: {
cache: true,
formatter: require.resolve('react-dev-utils/eslintFormatter'),
eslintPath: require.resolve('eslint'),
resolvePluginsRelativeTo: __dirname,
},
loader: require.resolve('eslint-loader'),
},
],
//=================== INCLUDED =====================/
//
// Included the lenrna packages directory (up directory)
// in order to transpile all files from other packages.
//
//===================================================
include: [path.resolve(__dirname, "../.."), paths.appSrc],
},
{
// "oneOf" will traverse all following loaders until one will
// match the requirements. When no loader matches it will fall
// back to the "file" loader at the end of the loader list.
oneOf: [
// "url" loader works like "file" loader except that it embeds assets
// smaller than specified limit in bytes as data URLs to avoid requests.
// A missing `test` is equivalent to a match.
{
test: [/\.bmp$/, /\.gif$/, /\.jpe?g$/, /\.png$/],
loader: require.resolve('url-loader'),
options: {
limit: imageInlineSizeLimit,
name: 'static/media/[name].[hash:8].[ext]',
},
},
// Process application JS with Babel.
// The preset includes JSX, Flow, TypeScript, and some ESnext features.
{
test: /\.(js|mjs|jsx|ts|tsx)$/,
/// Renato Mendes
/// This was added to support transpiling of monorepo modules.
/// See https://github.com/webpack/webpack/issues/6799
///
/// Original:
/// include: paths.appSrc
///
include: [path.resolve(__dirname, "../.."), path.resolve(paths.lernaRoot + "/packages"), paths.appSrc],
// include: paths.appSrc,
include: [paths.lernaRoot, paths.appSrc],
loader: require.resolve('babel-loader'),
options: {
customize: require.resolve(
'babel-preset-react-app/webpack-overrides'
),
plugins: [
[
require.resolve('babel-plugin-named-asset-import'),
{
loaderMap: {
svg: {
ReactComponent:
'@svgr/webpack?-svgo,+titleProp,+ref![path]',
},
},
},
],
],
// This is a feature of `babel-loader` for webpack (not Babel itself).
// It enables caching results in ./node_modules/.cache/babel-loader/
// directory for faster rebuilds.
cacheDirectory: true,
// See #6846 for context on why cacheCompression is disabled
cacheCompression: false,
compact: isEnvProduction,
},
},
// Process any JS outside of the app with Babel.
// Unlike the application JS, we only compile the standard ES features.
{
test: /\.(js|mjs)$/,
exclude: /@babel(?:\/|\\{1,2})runtime/,
loader: require.resolve('babel-loader'),
options: {
babelrc: false,
configFile: false,
compact: false,
presets: [
[
require.resolve('babel-preset-react-app/dependencies'),
{ helpers: true },
],
],
cacheDirectory: true,
// See #6846 for context on why cacheCompression is disabled
cacheCompression: false,
// If an error happens in a package, it's possible to be
// because it was compiled. Thus, we don't want the browser
// debugger to show the original code. Instead, the code
// being evaluated would be much more helpful.
sourceMaps: false,
},
},
// "postcss" loader applies autoprefixer to our CSS.
// "css" loader resolves paths in CSS and adds assets as dependencies.
// "style" loader turns CSS into JS modules that inject <style> tags.
// In production, we use MiniCSSExtractPlugin to extract that CSS
// to a file, but in development "style" loader enables hot editing
// of CSS.
// By default we support CSS Modules with the extension .module.css
{
test: cssRegex,
exclude: cssModuleRegex,
use: getStyleLoaders({
importLoaders: 1,
sourceMap: isEnvProduction && shouldUseSourceMap,
}),
// Don't consider CSS imports dead code even if the
// containing package claims to have no side effects.
// Remove this when webpack adds a warning or an error for this.
// See https://github.com/webpack/webpack/issues/6571
sideEffects: true,
},
// Adds support for CSS Modules (https://github.com/css-modules/css-modules)
// using the extension .module.css
{
test: cssModuleRegex,
use: getStyleLoaders({
importLoaders: 1,
sourceMap: isEnvProduction && shouldUseSourceMap,
modules: true,
getLocalIdent: getCSSModuleLocalIdent,
}),
},
// Opt-in support for SASS (using .scss or .sass extensions).
// By default we support SASS Modules with the
// extensions .module.scss or .module.sass
{
test: sassRegex,
exclude: sassModuleRegex,
use: getStyleLoaders(
{
importLoaders: 2,
sourceMap: isEnvProduction && shouldUseSourceMap,
},
'sass-loader'
),
// Don't consider CSS imports dead code even if the
// containing package claims to have no side effects.
// Remove this when webpack adds a warning or an error for this.
// See https://github.com/webpack/webpack/issues/6571
sideEffects: true,
},
// Adds support for CSS Modules, but using SASS
// using the extension .module.scss or .module.sass
{
test: sassModuleRegex,
use: getStyleLoaders(
{
importLoaders: 2,
sourceMap: isEnvProduction && shouldUseSourceMap,
modules: true,
getLocalIdent: getCSSModuleLocalIdent,
},
'sass-loader'
),
},
// "file" loader makes sure those assets get served by WebpackDevServer.
// When you `import` an asset, you get its (virtual) filename.
// In production, they would get copied to the `build` folder.
// This loader doesn't use a "test" so it will catch all modules
// that fall through the other loaders.
{
loader: require.resolve('file-loader'),
// Exclude `js` files to keep "css" loader working as it injects
// its runtime that would otherwise be processed through "file" loader.
// Also exclude `html` and `json` extensions so they get processed
// by webpacks internal loaders.
exclude: [/\.(js|mjs|jsx|ts|tsx)$/, /\.html$/, /\.json$/],
options: {
name: 'static/media/[name].[hash:8].[ext]',
},
},
// ** STOP ** Are you adding a new loader?
// Make sure to add the new loader(s) before the "file" loader.
],
},
],
}
...
我仍然收到错误，因为我的外部组件没有被转换。
如何使上述 webpack 配置转译驻留在我的 lerna 项目的另一个包中的代码？还缺少其他配置吗？我做错了什么？
最佳答案
坏消息:这是一个常见问题。 Create React App doesn't support monorepos ，截至 3.2.0/2019 年末。如果您想在 lerna 兄弟包之间共享组件，许多人要么避免使用“CRApp”，要么在其组件库包中包含构建脚本并提交和导出预编译的 ES5文件。
好消息:我发现了一个似乎有效的修复，并且不需要弹出 CRA。通过本地构建和测试部署到 github 页面进行了测试。
它使用 craco ，它提供了一个 API，用于编辑 CRA 的 webpack 配置而不弹出。 Craco 有添加 webpack 加载器等的插件；我们需要craco-babel-loader :
npm i --save @craco/craco craco-babel-loader
...然后还有一些进一步的 CRACO 设置步骤，请检查 https://github.com/gsoft-inc/craco/blob/master/packages/craco/README.md#installation最新的。在撰写本文时，您需要替换 package.json 中的以下 CRA scripts:
react-scripts 启动=>craco 启动react-scripts 构建=>craco 构建react-scripts 测试=>craco 测试
然后我们需要在 CRA/craco 包的根目录中创建一个配置文件 craco.config.js，该文件从同级包接收 ES6+ JSX 组件，我们需要列出要发送到 babel 的包名称:
// crago.config.js
// see: https://github.com/sharegate/craco
const path = require('path')
const fs = require('fs')
const cracoBabelLoader = require('craco-babel-loader')
// Handle relative paths to sibling packages
const appDirectory = fs.realpathSync(process.cwd())
const resolvePackage = relativePath => path.resolve(appDirectory, relativePath)
module.exports = {
plugins: [
{
plugin: cracoBabelLoader,
options: {
includes: [
// No "unexpected token" error importing components from these lerna siblings:
resolvePackage('../some-component-library'),
resolvePackage('../more-components'),
resolvePackage('../another-components-package'),
],
},
},
],
}
关于reactjs - 如何配置 webpack 来转译其他 lerna 包中的文件(从 create-react-app 中弹出)，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/58323916/