Q:

What do I return from my Gulp task if I decide to do nothing? 

Suppose my gulp task decides to do nothing -- what should I return? 
gulp.task 'maybe_transform_files', ->
    if check_something()
        gulp.src('src')
            .pipe transform_files()
            .pipe gulp.dest('target')
    else
        return something

In other situations, I might use the done() callback, but I don't think I can use it here, where I might return a stream. 

A:

have a look at gulp-nop 
what you can do to have no-op is
var nop = require('gulp-nop');

.....

return gulp.src('. ').pipe(nop());

or if you are using gulp-util you can use noop, similarly

