conn.clean deletes all the files without checking if a local file exists

[kolesnikov-sa]

I'm on Gulp 4 with vinyl-ftp, and I'm not sure why the code below does not work as expected — it just deletes all the files from /www/remote/ and it's subfolders as opposed to checking with local if the files are available and delete selectively:

function clean() {
    let conn = ftp.create({
        host: 'xxx',
        user: 'yyy',
        password: 'zzz',
        parallel: 10,
        log: log
    });

    let remoteFiles = '/www/remote/**/*.*';

    return conn.clean(remoteFiles, './build', {base: '/'});
}

The local files are located in ./build relatively to gulpfile.js. The remote files are located in /www/remote.