How to use the @stylable/node.findFiles function in @stylable/node

outputCSSNameTemplate,
    outputSources,
    injectCSSRequest,
    optimize,
    minify,
    compat,
    manifest
}: BuildOptions) {
    const generatorModule = generatorPath
        ? require(resolve(generatorPath))
        : require('./default-generator');
    const generator: Generator = new generatorModule.Generator();
    const blacklist = new Set(['node_modules']);
    const fullSrcDir = join(rootDir, srcDir);
    const fullOutDir = join(rootDir, outDir);
    const { result: filesToBuild } = findFiles(fs, fullSrcDir, extension, blacklist);
    const assets: string[] = [];
    const diagnosticsMsg: string[] = [];
    const indexFileOutput: Array<{ from: string; name: string }> = [];
    const nameMapping: { [key: string]: string } = {};

    if (filesToBuild.length === 0) {
        log('[Build]', 'No stylable files found. build skipped.');
    } else {
        log('[Build]', `Building ${filesToBuild.length} stylable files.`);
    }
    filesToBuild.forEach(filePath => {
        indexFile
            ? generateFileIndexEntry(
                  filePath,
                  nameMapping,
                  log,

private handleVariants(
        componentConfig: ComponentConfig,
        componentDir: string,
        compilation: webpack.compilation.Compilation,
        builder: ComponentMetadataBuilder,
        namespace: any,
        depth: any
    ) {
        if (componentConfig.variantsPath) {
            const variantsDir = join(componentDir, componentConfig.variantsPath);

            const { result: variants, errors } = findFiles(
                compilation.inputFileSystem,
                variantsDir,
                '.st.css',
                new Set(),
                true
            );
            if (errors.length) {
                throw new Error(
                    `Error while reading variants for: ${componentConfig.id} in ${variantsDir}\nOriginal Errors:\n${errors}`
                );
            }

            variants.forEach((name: string) => {
                if (!name.match(/\.st\.css/)) {
                    return;
                }