Webpack 4 Configurations to Build Multiple Gutenberg Blocks using @wordpress/scripts (see https://wordpress.stackexchange.com/q/390282/25324)

webpack.config.path-names.js

const path = require( 'path' );

const config = require( '@wordpress/scripts/config/webpack.config.js' );

const resolveSource = ( ...path_parts ) => path.resolve( process.cwd(), 'src', ...path_parts );
const resolveBlockEntry = ( name ) => resolveSource( 'blocks', name, 'index.js' );

config.entry = {
  'blocks/foo/index': resolveBlockEntry( 'foo' ),
  'blocks/bar/index': resolveBlockEntry( 'bar' ),
  'frontend/accordion': resolveSource( 'frontend', 'accordion.js' ),
};

config.optimization.splitChunks.cacheGroups.style.name = ( module, chunks, cache_group_key ) => {
  const delimeter = config.optimization.splitChunks.cacheGroups.style.automaticNameDelimiter;

  if( module.type === 'javascript/auto' )
    return `${cache_group_key}${delimeter}${chunks[0].name}`;
  
  return chunks[0].name.replace( /(\/?)([^/]+?)$/, `$1style${delimeter}$2` );
};

module.exports = config;