背景
react官方脚手架配置使用less书写、引入样式。
配置过程：
创建react项目
npx create-react-app my-app
cd my-app
npm start
暴露配置文件
npm run eject
如上图所示配置文件
安装less相关包
npm i less@4.1.1 --save
npm i less-loader@5.0.0 --save
推荐使用上述版本，实践可用。
webpack.config.js中的配置
1.添加less文件的正则匹配
// 添加less配置
const lessRegex = /\.less$/;
const lessModuleRegex = /\.module\.less$/;
2.找到css的解析配置，仿写less
css的排至如下：
{
test: cssRegex,
exclude: cssModuleRegex,
use: getStyleLoaders({
importLoaders: 1,
sourceMap: isEnvProduction
? shouldUseSourceMap
: isEnvDevelopment,
}),
// 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
: isEnvDevelopment,
modules: {
getLocalIdent: getCSSModuleLocalIdent,
},
}),
},
在上方css配置的下方配置less，如下：
{
test: lessRegex,
exclude: lessModuleRegex,
use: getStyleLoaders(
{
importLoaders: 2,
sourceMap: isEnvProduction
? shouldUseSourceMap
: isEnvDevelopment,
},
"less-loader"
),
sideEffects: true,
},
{
test: lessModuleRegex,
use: getStyleLoaders(
{
importLoaders: 2,
sourceMap: isEnvProduction
? shouldUseSourceMap
: isEnvDevelopment,
modules: {
getLocalIdent: getCSSModuleLocalIdent,
},
},
"less-loader"
),
},
3.开启Less的javascriptEnabled，比如接入ant landing时
找到如下函数
getStyleLoaders
其完整函数如下
const getStyleLoaders = (cssOptions, preProcessor) => {
const loaders = [
isEnvDevelopment && require.resolve('style-loader'),
isEnvProduction && {
loader: MiniCssExtractPlugin.loader,
// css is located in `static/css`, use '../../' to locate index.html folder
// in production `paths.publicUrlOrPath` can be a relative path
options: paths.publicUrlOrPath.startsWith('.')
? { publicPath: '../../' }
: {},
},
{
loader: require.resolve('css-loader'),
options: cssOptions,
},
{
// Options for PostCSS as we reference these options twice
// Adds vendor prefixing based on your specified browser support in
// package.json
loader: require.resolve('postcss-loader'),
options: {
// Necessary for external CSS imports to work
// https://github.com/facebook/create-react-app/issues/2677
ident: 'postcss',
plugins: () => [
require('postcss-flexbugs-fixes'),
require('postcss-preset-env')({
autoprefixer: {
flexbox: 'no-2009',
},
stage: 3,
}),
// Adds PostCSS Normalize as the reset css with default options,
// so that it honors browserslist config in package.json
// which in turn let's users customize the target behavior as per their needs.
postcssNormalize(),
],
sourceMap: isEnvProduction ? shouldUseSourceMap : isEnvDevelopment,
},
},
].filter(Boolean);
if (preProcessor) {
loaders.push(
{
loader: require.resolve('resolve-url-loader'),
options: {
sourceMap: isEnvProduction ? shouldUseSourceMap : isEnvDevelopment,
root: paths.appSrc,
},
},
{
loader: require.resolve(preProcessor),
options: {
sourceMap: true,
},
}
);
}
return loaders;
};
函数下方拷贝如下：
const getStyleLoaders = (cssOptions,lessOptions, preProcessor) => {
const loaders = [
isEnvDevelopment && require.resolve("style-loader"),
isEnvProduction && {
loader: MiniCssExtractPlugin.loader,
// css is located in `static/css`, use '../../' to locate index.html folder
// in production `paths.publicUrlOrPath` can be a relative path
options: paths.publicUrlOrPath.startsWith(".")
? { publicPath: "../../" }
: {},
},
// 新加less
{
loader: require.resolve("css-loader"),
options: cssOptions,
},
{
loader: require.resolve("less-loader"),
options: lessOptions,
},
{
// Options for PostCSS as we reference these options twice
// Adds vendor prefixing based on your specified browser support in
// package.json
loader: require.resolve("postcss-loader"),
options: {
// Necessary for external CSS imports to work
// https://github.com/facebook/create-react-app/issues/2677
ident: "postcss",
plugins: () => [
require("postcss-flexbugs-fixes"),
require("postcss-preset-env")({
autoprefixer: {
flexbox: "no-2009",
},
stage: 3,
}),
// Adds PostCSS Normalize as the reset css with default options,
// so that it honors browserslist config in package.json
// which in turn let's users customize the target behavior as per their needs.
postcssNormalize(),
],
sourceMap: isEnvProduction ? shouldUseSourceMap : isEnvDevelopment,
},
},
].filter(Boolean);
if (preProcessor) {
loaders.push(
{
loader: require.resolve("resolve-url-loader"),
options: {
sourceMap: isEnvProduction ? shouldUseSourceMap : isEnvDevelopment,
root: paths.appSrc,
},
},
{
loader: require.resolve(preProcessor),
options: {
sourceMap: true,
},
}
);
}
return loaders;
};
主要变更：
项目重启，试试less导入和less module的导入
第一种方式：
import './app.less'
第二种方式：
//module命名规则
xxx.module.less
导入
import styles from './app.module.less'
元素类名引入
//使用
className={styles.xxx}
