vue.config.js

const path = require( 'path' );
const { CKEditorTranslationsPlugin } = require('@ckeditor/ckeditor5-dev-translations');
const { styles } = require( '@ckeditor/ckeditor5-dev-utils' );

module.exports = {
    // The source of CKEditor is encapsulated in ES6 modules. By default, the code
    // from the node_modules directory is not transpiled, so you must explicitly tell
    // the CLI tools to transpile JavaScript files in all ckeditor5-* modules.
    devServer: {
        host: '127.0.0.1',
        port: 8080,
    },
    transpileDependencies: [
        /ckeditor5-[^/\\]+[/\\]src[/\\].+\.js$/,
    ],

    configureWebpack: {
        devtool: 'source-map',
        plugins: [
            // CKEditor needs its own plugin to be built using webpack.
            new CKEditorTranslationsPlugin( {
                // See https://ckeditor.com/docs/ckeditor5/latest/features/ui-language.html
                language: 'en',

                // Append translations to the file matching the `app` name.
                translationsOutputFile: 'app'
            } )
        ]
    },

    // Vue CLI would normally use its own loader to load .svg and .css files, however:
    //	1. The icons used by CKEditor must be loaded using raw-loader,
    //	2. The CSS used by CKEditor must be transpiled using PostCSS to load properly.
    chainWebpack: config => {
        // (1.) To handle editor icons, get the default rule for *.svg files first:
        const svgRule = config.module.rule( 'svg' );

        // Then you can either:
        //
        // * clear all loaders for existing 'svg' rule:
        //
        //		svgRule.uses.clear();
        //
        // * or exclude ckeditor directory from node_modules:
        svgRule.exclude.add( path.join( __dirname, 'node_modules', '@ckeditor' ) );

        // Add an entry for *.svg files belonging to CKEditor. You can either:
        //
        // * modify the existing 'svg' rule:
        //
        //		svgRule.use( 'raw-loader' ).loader( 'raw-loader' );
        //
        // * or add a new one:

        config.module
            .rule( 'cke-svg' )
            .test( /ckeditor5-[^/\\]+[/\\]theme[/\\]icons[/\\][^/\\]+\.svg$/ )
            .use( 'raw-loader' )
            .loader( 'raw-loader' );

        // (2.) Transpile the .css files imported by the editor using PostCSS.
        // Make sure only the CSS belonging to ckeditor5-* packages is processed this way.
        config.module
            .rule( 'cke-css' )
            .test( /ckeditor5-[^/\\]+[/\\].+\.css$/ )
            .use( 'postcss-loader' )
            .loader( 'postcss-loader' )
            .tap( () => {
                return {
                    postcssOptions: styles.getPostCssConfig( {
                        themeImporter: {
                            themePath: require.resolve( '@ckeditor/ckeditor5-theme-lark' )
                        },
                        minify: true
                    } )
                };
            } );
    }
};