gulp-sketch task not completing

[ronakdigite]

Hi,
I am trying to run an independent gulp task, which will convert all my sketch files in a folder to pngs in another folder.

I am running the following task as per the given syntax:

gulp.task('sketch', function(){
return gulp.src('sketch-files/*.sketch')
.pipe(sketch({
export: 'artboards',
formats: 'png'
})).on('error', gutil.log)
.pipe(gulp.dest('preview'));
});

The task starts but never ends and i am thrown out of the gulp task. No pngs generated either...
I am using gulp-sketch 1.0.5 and sketch version 45.2

Folder structure,
---gulpfile.js
---sketch-files
---preview
all at the same level

Terminal Output: