Search code examples
webpackreloadwebpack-dev-serverpostcsswebpack-hmr

Webpack and Precss not reloading on @import file change

I am setting up a basic Webpack installation and want to have automatic browser reloading of preprocessed CSS in @imported files using PostCSS and the PreCSS plugin. At present if I modify and save an @imported file the browser does not refresh (body.css in below example). If I then save the root referenced CSS file (styles.css) then the browser refreshes and also reflects any changes made to the @imported file.

I have tried with using the configurable webpack-dev-server, and using a server.js. I have tried without and with hot model reloading (HMR) installed.

Is there a way to have webpack watch @imported CSS files, or am I fundamentally missing something here?

package.json

"dependencies": {
  "react": "^0.14.0",
  "react-dom": "^0.14.0"
},
"devDependencies": {
  "autoprefixer": "^6.3.1",
  "css-loader": "^0.23.1",
  "extract-text-webpack-plugin": "^1.0.1",
  "postcss-loader": "^0.8.0",
  "postcss-scss": "^0.1.3",
  "precss": "^1.4.0",
  "react-hot-loader": "^1.3.0",
  "style-loader": "^0.13.0",
  "webpack": "^1.12.13",
  "webpack-dev-server": "^1.14.1"
},
"scripts": {
  "test": "echo \"Error: no test specified\" && exit 1",
  "start": "node server.js",
  "start-dev-server": "webpack-dev-server 'webpack-dev-server/client?/' --host 0.0.0.0 --port 9090 --progress --colors",
  "build": "echo \"Build hasn't been specified yet\" && exit 1"
},

webpack.config.js

/*global require module __dirname*/
var path = require('path'),
    webpack = require('webpack'),
    ExtractTextPlugin = require('extract-text-webpack-plugin'),
    autoprefixer = require('autoprefixer'),
    precss = require('precss');

module.exports = {
    entry: [
    'webpack-dev-server/client?http://localhost:9090',
    'webpack/hot/only-dev-server',
    './entry.js'
  ],
    output: {
        path: path.join(__dirname, 'dist'),
        filename: 'bundle.js',
        publicPath: '/static/'
    },
    devtool: 'source-map',
    module: {
        loaders: [
            { 
                test: /\.css$/i,
                loaders: ExtractTextPlugin.extract('style-loader', 'css-loader?sourceMap&modules&importLoaders=1!postcss-loader')
            }
        ]
    },
    postcss: function() {
        return [precss, autoprefixer];
    },
    plugins: [
        // Set the name of the single CSS file here.
        new ExtractTextPlugin('main.css', { allChunks: true }),
        new webpack.HotModuleReplacementPlugin()
    ]
};

index.html

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <link rel="stylesheet" type="text/css" href="/static/main.css" />
    </head>
    <body>
        <script src="http://localhost:9090/webpack-dev-server.js"></script>
        <script type="text/javascript" src="/static/bundle.js" charset="utf-8"></script>
    </body>
</html>

entry.js

require("./styles.css");
document.write(require("./content.js"));

styles.css

@import "body.css";

body {
     /*background: yellow; */
    font-size: 30px;
}

div {
    display: flex;
}

body.css

$color: yellow;

body {
    background: $color;
}

div {
    color: white;

    a {
        color: green;
    }
}

div {
    display: flex;
}
Solution

  • After much searching on the internet the answer can be found in these two threads:

    1. https://github.com/postcss/postcss-loader/issues/8
    2. https://github.com/jonathantneal/precss/issues/6

    Thanks to @zzq889 for the following example using postcss-import which gets around the limitation in postcss-partial-import:

    var postcssImport = require('postcss-import');

...

postcss: function (webpack) {
    return [
        postcssImport({
            addDependencyTo: webpack
        })
    ];
}

    This will hopefully in future be working with just precss and its dependent library postcss-partial-import with this pull request or a solution based on it.