Gulp reccuring functions not ending?

Question

I have a problem with returns in a special function that I'm using to generate styles.

I have 3 stylesheets to generate, that have different file names/variables. So I created a function instead of duplicating the code.

The problem I'm having is these task do not complete. I tried adding callback functions to the sass task, it does finish the task but it seems the generateStyles just never really returns or finish.

What am I missing?

Thanks in advance,

gulp.task('sass', function () {
  generateStyle('summer');
  generateStyle('winter');
  generateStyle('spring');
});

function generateStyle(season) {
    if (season == undefined) {
        console.log('no season setted in generateStyle');
        return;
    }

    return gulp.src('assets/styles/all.scss')
     .pipe(insert.prepend('@import "assets/styles/seasons/'+ season +'.scss";'))
     .pipe(sass({includePaths: ['node_modules'],outputStyle: 'compressed'}).on('error', sass.logError))
     .pipe(sourcemaps.write())
      .pipe(rename('all-'+ season +'.css'))
      .pipe(gulp.dest(assetsOutputPath + 'css'));

      // should I add a callback here? or a promise?

}

// Main watch
gulp.task('default', function() {
  gulp.watch('assets/styles/**/*.scss',  gulp.series('sass'));
});

Answer 1

From what I understood, the task itself must return a stream. So I wrapped the stylesheets into individual tasks and it works, without the use of callbacks or promise. See below.

// The function
function generateStyle(season) {
    if (season == undefined) {
        console.log('no season setted in generateStyle');
        return;
    }

    return gulp.src('assets/styles/all.scss')
     .pipe(insert.prepend('@import "assets/styles/seasons/'+ season +'.scss";'))
     .pipe(sass({includePaths: ['node_modules'],outputStyle: 'compressed'}).on('error', sass.logError))
     .pipe(sourcemaps.write())
      .pipe(rename('all-'+ season +'.css'))
      .pipe(gulp.dest(assetsOutputPath + 'css'));

}

// Individual tasks
gulp.task('styles-winter', function(){
    return generateStyle('winter');
});
gulp.task('styles-spring', function(){
    return generateStyle('spring');
});
gulp.task('styles-summer', function(){
    return generateStyle('summer');
});

// Main watch
gulp.task('default', function() {
  gulp.watch('assets/styles/**/*.scss',  gulp.series('styles-winter', 'styles-summer', 'styles-spring'));
});