How to use the @automattic/calypso-build/webpack/file-loader.loader function in @automattic/calypso-build

let outputFilename = '[name].[chunkhash].min.js'; // prefer the chunkhash, which depends on the chunk, not the entire build
let outputChunkFilename = '[name].[chunkhash].min.js'; // ditto

// we should not use chunkhash in development: https://github.com/webpack/webpack-dev-server/issues/377#issuecomment-241258405
// also we don't minify so dont name them .min.js
//
// Desktop: no chunks or dll here, just one big file for the desktop app
if ( isDevelopment || isDesktop ) {
	outputFilename = '[name].js';
	outputChunkFilename = '[name].js';
}

const cssFilename = cssNameFromFilename( outputFilename );
const cssChunkFilename = cssNameFromFilename( outputChunkFilename );

const fileLoader = FileConfig.loader(
	// The server bundler express middleware server assets from the hard-coded publicPath `/calypso/evergreen/`.
	// This is required so that running calypso via `npm start` doesn't break.
	isDevelopment
		? {
				outputPath: 'images',
				publicPath: '/calypso/evergreen/images/',
		  }
		: {
				// File-loader does not understand absolute paths so __dirname won't work.
				// Build off `output.path` for a result like `/…/public/evergreen/../images/`.
				outputPath: path.join( '..', 'images' ),
				publicPath: '/calypso/images/',
				emitFile: browserslistEnv === defaultBrowserslistEnv, // Only output files once.
		  }
);

* Internal dependencies
 */
const cacheIdentifier = require( './server/bundler/babel/babel-loader-cache-identifier' );
const config = require( 'config' );
const bundleEnv = config( 'env' );
const { workerCount } = require( './webpack.common' );
const TranspileConfig = require( '@automattic/calypso-build/webpack/transpile' );
const nodeExternals = require( 'webpack-node-externals' );
const FileConfig = require( '@automattic/calypso-build/webpack/file-loader' );

/**
 * Internal variables
 */
const isDevelopment = bundleEnv === 'development';

const fileLoader = FileConfig.loader( {
	publicPath: isDevelopment ? '/calypso/evergreen/images/' : '/calypso/images/',
	emitFile: false, // On the server side, don't actually copy files
} );

const commitSha = process.env.hasOwnProperty( 'COMMIT_SHA' ) ? process.env.COMMIT_SHA : '(unknown)';

/**
 * This lists modules that must use commonJS `require()`s
 * All modules listed here need to be ES5.
 *
 * @returns {Array} list of externals
 */
function getExternals() {
	return [
		// Don't bundle any node_modules, both to avoid a massive bundle, and problems
		// with modules that are incompatible with webpack bundling.

} ),
		},
		module: {
			rules: [
				TranspileConfig.loader( {
					workerCount,
					configFile: path.join( __dirname, 'babel.config.js' ),
					cacheDirectory: path.join( __dirname, '.cache' ),
					exclude: /node_modules\//,
				} ),
				SassConfig.loader( {
					preserveCssCustomProperties: false,
					includePaths: [ path.join( __dirname, 'client' ) ],
					prelude: '@import "~@automattic/calypso-color-schemes/src/shared/colors";',
				} ),
				FileConfig.loader(),
			],
		},
		resolve: {
			extensions: [ '.json', '.js', '.jsx' ],
			modules: [ 'node_modules' ],
		},
		node: false,
		plugins: [
			new webpack.DefinePlugin( {
				'process.env.NODE_ENV': JSON.stringify( process.env.NODE_ENV ),
				global: 'window',
			} ),
			new webpack.IgnorePlugin( /^\.\/locale$/, /moment$/ ),
			...SassConfig.plugins( { cssFilename, minify: ! isDevelopment } ),
			new DuplicatePackageCheckerPlugin(),
			new CopyWebpackPlugin( [