Javascript modifications

Hello everyone,
What would you advise to make changes to the jss files of a theme?
Mimicking the approach described in the mkdocs to modify css fileswith the Gulp task called css, I tried to add a Gulp task for jss but with no success so far, my changes do not appear.

// configure the jshint task
gulp.task('jshint', function() {
  return gulp.src('./asset/js/*.js')

// configure which files to watch and what tasks to use on file changes
gulp.task('jshint:watch', function() {'./asset/js/*.js', ['jshint']);

I must say these are a bit new for me, thank you in advance for your ideas!