gulp plugin returning promise

gulp plugin returning promise

const though = require("through2"),
    syncDB = require("../syncdb");


module.exports = function() {
    return through.obj(function(file, enc, cb) {

        console.log(file.path, enc);

        if (file.isNull()) {
            // return empty file
            return cb(null, file);
        }

        syncDB(file.path)
            .then(function() {
                cb(null, file);
            }).catch(function(e) {
                cb(e, null);
            });
    });
}