Question

使用热重载运行webpack-dev-server，每次更改scss文件时，重新编译需要3秒以上，而js / html只需不到1秒即可重新编译。我无法弄清楚原因。

这是我的配置：

webpack.common.js

const path = require("path");
const HtmlWebpackPlugin = require("html-webpack-plugin");
const CleanWebpackPlugin = require("clean-webpack-plugin");
const CopyWebpackPlugin = require("copy-webpack-plugin");

module.exports = {
    entry: {
        index: "./webpack.entry.js",
        style: "./app/scss/main/app.scss"
    },
    module: {
        rules: [
            {
                test: /\.js$/,
                use: {
                    loader: "babel-loader",
                    options: {
                        presets: ["@babel/preset-env"],
                        cacheDirectory: true
                    }
                }
            }
        ]
    },
    plugins: [
        new CleanWebpackPlugin(["dist"]),
        new HtmlWebpackPlugin({
            template: "./app/html/index.html"
        })
    ],
    output: {
        path: path.resolve(__dirname, "dist")
    }
};

webpack.dev.js

const webpack = require("webpack");
const merge = require("webpack-merge");
const common = require("./webpack.common.js");

module.exports = merge(common, {
    devtool: "cheap-module-eval-source-map",
    devServer: {
        contentBase: "./dist",
        port: 9000,
        hot: true
    },
    module: {
        rules: [
            {
                test: /\.scss$/,
                use: [
                    {
                        loader: "style-loader"
                    },
                    {
                        loader: "css-loader",
                        options: {
                            sourceMap: true,
                            url: false
                        }
                    },
                    {
                        loader: "sass-loader",
                        options: {
                            sourceMap: true
                        }
                    }
                ]
            }
        ]
    },
    plugins: [new webpack.HotModuleReplacementPlugin()],
    output: {
        filename: "[name].js"
    },
    mode: "development"
});

app.scss是一堆scss导入，可能导致另一堆scss导入。

@import "../base";
@import "../layout";
@import "../modules";
@import "../state";
@import "../3rdparty";

/* components */
@import "../../component/footer/footer";
@import "../../component/switcher/switcher";
@import "../../component/header/header";
@import "../../component/dropdown/dropdown";
@import "../../component/lgntabset/lgntabset";
@import "../../component/lgnprogressstep/lgnprogressstep";
@import "../../component/lgnwizard/lgnwizard";
@import "../../component/lgnslider/lgnslider";
@import "../../component/lgndropdown/lgndropdown";
@import "../../component/lgnmodal/lgnmodal";
@import "../../component/calendar/weeklycalendar/calendarwidget";

如何改善scss重新编译时间？

Answer 1

不幸的是，这是一个众所周知的问题：https://github.com/webpack-contrib/sass-loader/issues/296，你可以做很多事情。您的配置是正确的。

还有另一种https://github.com/yibn2008/fast-sass-loader，声称速度提高了5~10倍。我对此没有任何经验，但也许值得一试。

Answer 2

我最终做了与create-react-app的{{3}}类似的事情：

将node-sass-chokidar --watch作为单独的进程运行，每次修改scss文件时都会生成css文件。
在JS和Webpack配置中，引用生成的CSS文件。

这将重新编译时间减少到约1秒，这比fast-sass-loader（~2秒）更好。

<强>更新

如果您不需要解析URL()和@import，只需使用raw-loader，这会将我的重新编译减少到大约0.5秒！

Webpack 4：重新编译scss需要3秒以上

2 个答案: