Compiling bootstrap scss with webpack in .Net Core Angular Template

Question

I am attempting to use the bootstrap scss files instead of the css file so I can override the bootstrap variables. I can get the styles to load using the css file but not using scss files. I am doing so in a .NET Core Angular project created from the Visual Studio 2017 Angular template.

I have tried the answers here but have had no luck.

Spa template .net core 2.0 angular 4 webpack 2 use sass not boostrap 4 css

Here is my understanding of how it should work:

• The webpack.config.vendor.js file generates vendor.js and vendor.css. I understand vendor.js is kept separate from main-client.js so that it only needs to be built when the vendor dependencies change, improving the build process and only doing cache busting when needed for production publishes.

• In the scenario where I want to compile bootstrap's scss files instead of using their css files, I expect that the bootstrap.css reference in webpack.config.vendor.js should be REMOVED and instead a scss rule is added to webpack.config.js.

• Webpack.config.js generates a main-client.js file that includes all the js code needed for the angular components. And by inluding the scss rule in the config, it should also compile the bootstrap scss files into styles that are injected in the html header via javascript.

• A styles.scss file in my app is processed by webpack.config.js and should have @import "~bootstrap/scss/bootstrap" so that the bootstrap scss files are built. Ultimately I would also import my own _custom.scss file where I override the variables.

Is my understanding correct?

Also, I don't know what keeps webpack.config.js from processing the bootstrap scss files under the node-modules folder in addition to my style.scss file (which already imports bootstrap.scss). Is that something I need to define in webpack.js?

Here is my webpack.config.js. The scss rule is straight from the bootstrap documentation.

const path = require('path');
const webpack = require('webpack');
const merge = require('webpack-merge');
const AotPlugin = require('@ngtools/webpack').AotPlugin;
const CheckerPlugin = require('awesome-typescript-loader').CheckerPlugin;

module.exports = (env) => {
    // Configuration in common to both client-side and server-side bundles
    const isDevBuild = !(env && env.prod);
    const sharedConfig = {
        stats: { modules: false },
        context: __dirname,
        resolve: { extensions: ['.js', '.ts'] },
        output: {
            filename: '[name].js',
            publicPath: 'dist/' // Webpack dev middleware, if enabled, handles requests for this URL prefix
        },
        module: {
            rules: [
                { test: /\.ts$/, include: /ClientApp/, use: isDevBuild ? ['awesome-typescript-loader?silent=true', 'angular2-template-loader'] : '@ngtools/webpack' },
                { test: /\.html$/, use: 'html-loader?minimize=false' },
                { test: /\.css$/, use: ['to-string-loader', isDevBuild ? 'css-loader' : 'css-loader?minimize'] },
                { test: /\.(png|jpg|jpeg|gif|svg)$/, use: 'url-loader?limit=25000' },
                {
                    test: /\.(scss)$/,
                    use: [{
                        loader: 'style-loader', // inject CSS to page
                    }, {
                        loader: 'css-loader', // translates CSS into CommonJS modules
                    }, {
                        loader: 'postcss-loader', // Run post css actions
                        options: {
                            plugins: function () { // post css plugins, can be exported to postcss.config.js
                                return [
                                    require('precss'),
                                    require('autoprefixer')
                                ];
                            }
                        }
                    }, {
                        loader: 'sass-loader' // compiles SASS to CSS
                    }]
                },
            ]
        },
        plugins: [new CheckerPlugin()]
    };

    // Configuration for client-side bundle suitable for running in browsers
    const clientBundleOutputDir = './wwwroot/dist';
    const clientBundleConfig = merge(sharedConfig, {
        entry: { 'main-client': './ClientApp/boot.browser.ts' },
        output: { path: path.join(__dirname, clientBundleOutputDir) },
        plugins: [
            new webpack.DllReferencePlugin({
                context: __dirname,
                manifest: require('./wwwroot/dist/vendor-manifest.json')
            }),
            new webpack.ProvidePlugin({
                $: 'jquery',
                jQuery: 'jquery',
                'window.jQuery': 'jquery',
                Popper: ['popper.js', 'default']
                // In case you imported plugins individually, you must also require them here:
                //Util: "exports-loader?Util!bootstrap/js/dist/util",
                //Dropdown: "exports-loader?Dropdown!bootstrap/js/dist/dropdown"
            })
        ].concat(isDevBuild ? [
            // Plugins that apply in development builds only
            new webpack.SourceMapDevToolPlugin({
                filename: '[file].map', // Remove this line if you prefer inline source maps
                moduleFilenameTemplate: path.relative(clientBundleOutputDir, '[resourcePath]') // Point sourcemap entries to the original file locations on disk
            })
        ] : [
                // Plugins that apply in production builds only
                new webpack.optimize.UglifyJsPlugin(),
                new AotPlugin({
                    tsConfigPath: './tsconfig.json',
                    entryModule: path.join(__dirname, 'ClientApp/app/app-browser.module#AppModule'),
                    exclude: ['./**/*.server.ts']
                })
            ])
    });

    // Configuration for server-side (prerendering) bundle suitable for running in Node
    const serverBundleConfig = merge(sharedConfig, {
        resolve: { mainFields: ['main'] },
        entry: { 'main-server': './ClientApp/boot.server.ts' },
        plugins: [
            new webpack.DllReferencePlugin({
                context: __dirname,
                manifest: require('./ClientApp/dist/vendor-manifest.json'),
                sourceType: 'commonjs2',
                name: './vendor'
            })
        ].concat(isDevBuild ? [] : [
            // Plugins that apply in production builds only
            new AotPlugin({
                tsConfigPath: './tsconfig.json',
                entryModule: path.join(__dirname, 'ClientApp/app/app-server.module#AppModule'),
                exclude: ['./**/*.browser.ts']
            })
        ]),
        output: {
            libraryTarget: 'commonjs',
            path: path.join(__dirname, './ClientApp/dist')
        },
        target: 'node',
        devtool: 'inline-source-map'
    });

    return [clientBundleConfig, serverBundleConfig];
};

Here is my webpack.config.vendor.js. I have commented out bootstrap/dist/css/bootstrap.css

//Run from Command Line: webpack --config webpack.config.vendor.js

const path = require('path');
const webpack = require('webpack');
const ExtractTextPlugin = require('extract-text-webpack-plugin');
const merge = require('webpack-merge');
const treeShakableModules = [
    '@angular/animations',
    '@angular/common',
    '@angular/compiler',
    '@angular/core',
    '@angular/forms',
    '@angular/http',
    '@angular/platform-browser',
    '@angular/platform-browser-dynamic',
    '@angular/router',
    'zone.js',
];
const nonTreeShakableModules = [
    'bootstrap',
    //'bootstrap/dist/css/bootstrap.css',
    'ag-grid/dist/styles/ag-grid.css',
    'ag-grid/dist/styles/ag-theme-blue.css',
    'es6-promise',
    'es6-shim',
    'event-source-polyfill',
    'jquery',
];
const allModules = treeShakableModules.concat(nonTreeShakableModules);

module.exports = (env) => {
    const extractCSS = new ExtractTextPlugin('vendor.css');
    const isDevBuild = !(env && env.prod);
    const sharedConfig = {
        stats: { modules: false },
        resolve: { extensions: ['.js'] },
        module: {
            rules: [
                { test: /\.(png|woff|woff2|eot|ttf|svg)(\?|$)/, use: 'url-loader?limit=100000' }
            ]
        },
        output: {
            publicPath: 'dist/',
            filename: '[name].js',
            library: '[name]_[hash]'
        },
        plugins: [
            new webpack.ProvidePlugin({ $: 'jquery', jQuery: 'jquery' }), // Maps these identifiers to the jQuery package (because Bootstrap expects it to be a global variable)
            new webpack.ContextReplacementPlugin(/\@angular\b.*\b(bundles|linker)/, path.join(__dirname, './ClientApp')), // Workaround for https://github.com/angular/angular/issues/11580
            new webpack.ContextReplacementPlugin(/angular(\\|\/)core(\\|\/)@angular/, path.join(__dirname, './ClientApp')), // Workaround for https://github.com/angular/angular/issues/14898
            new webpack.IgnorePlugin(/^vertx$/) // Workaround for https://github.com/stefanpenner/es6-promise/issues/100
        ]
    };

    const clientBundleConfig = merge(sharedConfig, {
        entry: {
            // To keep development builds fast, include all vendor dependencies in the vendor bundle.
            // But for production builds, leave the tree-shakable ones out so the AOT compiler can produce a smaller bundle.
            vendor: isDevBuild ? allModules : nonTreeShakableModules
        },
        output: { path: path.join(__dirname, 'wwwroot', 'dist') },
        module: {
            rules: [
                { test: /\.css(\?|$)/, use: extractCSS.extract({ use: isDevBuild ? 'css-loader' : 'css-loader?minimize' }) }
            ]
        },
        plugins: [
            extractCSS,
            new webpack.DllPlugin({
                path: path.join(__dirname, 'wwwroot', 'dist', '[name]-manifest.json'),
                name: '[name]_[hash]'
            })
        ].concat(isDevBuild ? [] : [
            new webpack.optimize.UglifyJsPlugin()
        ])
    });

    const serverBundleConfig = merge(sharedConfig, {
        target: 'node',
        resolve: { mainFields: ['main'] },
        entry: { vendor: allModules.concat(['aspnet-prerendering']) },
        output: {
            path: path.join(__dirname, 'ClientApp', 'dist'),
            libraryTarget: 'commonjs2',
        },
        module: {
            rules: [{ test: /\.css(\?|$)/, use: ['to-string-loader', isDevBuild ? 'css-loader' : 'css-loader?minimize'] }]
        },
        plugins: [
            new webpack.DllPlugin({
                path: path.join(__dirname, 'ClientApp', 'dist', '[name]-manifest.json'),
                name: '[name]_[hash]'
            })
        ]
    });

    return [clientBundleConfig, serverBundleConfig];
}

Answer 1

Of course, as soon as I post the question, I figure it out.

The issue was that I needed to import the style.scss in my entry point module boot.browser.ts. Which also answers the question about how webpack knows to compile just the styles.scss and not all the bootstrap.scss files.