module.exports = { description: 'transformers can be asynchronous', options: { plugins: [ { transform: function ( code ) { return Promise.resolve( code.replace( 'x', 1 ) ); } }, { transform: function ( code ) { return code.replace( '1', 2 ); } }, { transform: function ( code ) { return Promise.resolve( code.replace( '2', 3 ) ); } } ] } };