How to use the metro-react-native-babel-transformer.transform function in metro-react-native-babel-transformer

process(src /*: string */, file /*: string */) {
    if (nodeFiles.test(file)) {
      // node specific transforms only
      return babelTransformSync(src, {
        filename: file,
        sourceType: 'script',
        ...nodeOptions,
        ast: false,
      }).code;
    }

    const {ast} = transformer.transform({
      filename: file,
      options: {
        ast: true, // needed for open source (?) https://github.com/facebook/react-native/commit/f8d6b97140cffe8d18b2558f94570c8d1b410d5c#r28647044
        dev: true,
        enableBabelRuntime: false,
        experimentalImportSupport: false,
        hot: false,
        inlineRequires: true,
        minify: false,
        platform: '',
        projectRoot: '',
        publicPath: '/assets',
        retainLines: true,
        sourceType: 'unambiguous', // b7 required. detects module vs script mode
      },
      src,

process(src /*: string */, file /*: string */) {
		if (nodeFiles.test(file)) {
			// node specific transforms only
			return babelTransformSync(src, {
				filename: file,
				sourceType: 'script',
				...nodeOptions,
				ast: false
			}).code;
		}

		const { ast } = transformer.transform({
			filename: file,
			options: {
				ast: true, // needed for open source (?) https://github.com/facebook/react-native/commit/f8d6b97140cffe8d18b2558f94570c8d1b410d5c#r28647044
				dev: true,
				enableBabelRuntime: false,
				experimentalImportSupport: false,
				hot: false,
				// NOTE: Commenting this line out allows our tests to run and pass
				// as expected.
				// See: https://github.com/facebook/react-native/issues/22175#issuecomment-436959462
				// inlineRequires: true,
				minify: false,
				platform: '',
				projectRoot: '',
				retainLines: true,
				sourceType: 'unambiguous' // b7 required. detects module vs script mode

process(src /*: string */, file /*: string */) {
    if (nodeFiles.test(file)) {
      // node specific transforms only
      return babelTransformSync(src, {
        filename: file,
        sourceType: 'script',
        ...nodeOptions,
        ast: false,
      }).code;
    }

    const {ast} = transformer.transform({
      filename: file,
      options: {
        ast: true, // needed for open source (?) https://github.com/facebook/react-native/commit/f8d6b97140cffe8d18b2558f94570c8d1b410d5c#r28647044
        dev: true,
        enableBabelRuntime: false,
        experimentalImportSupport: false,
        hot: false,
        inlineRequires: true,
        minify: false,
        platform: '',
        projectRoot: '',
        publicPath: '/assets',
        retainLines: true,
        sourceType: 'unambiguous', // b7 required. detects module vs script mode
      },
      src,

process(src, file) {
    const { ast } = transformer.transform({
      filename: file,
      options: {
        ast: true,
        dev: true,
        enableBabelRuntime: false,
        experimentalImportSupport: false,
        hot: false,
        inlineRequires: false,
        minify: false,
        platform: '',
        projectRoot: '',
        retainLines: true,
        sourceType: 'unambiguous',
      },
      src,
      plugins: metroBabelRegister.config.plugins,

module.exports.transform = function({ src, filename, options }) {
  if (filename.endsWith(".scss")) {
    return sassTransformer
      .renderToCSS({ src, filename, options })
      .then(css =>
        postCSSTransformer.transform({ src: css, filename, options })
      );
  } else if (filename.endsWith(".css")) {
    return postCSSTransformer.transform({ src, filename, options });
  } else {
    return upstreamTransformer.transform({ src, filename, options });
  }
};