gulpSassFunction.js

// Convert sass to css
gulp.task('sass', function(){
  return gulp.src('scss/**/*.scss')
    // Initializes sourcemaps
    .pipe(sourcemaps.init())
    .pipe(sass({
      errLogToConsole: true
     }))
    // Writes sourcemaps into the CSS file
    .pipe(sourcemaps.write())
    .pipe(gulp.dest('css'))
    .pipe(browserSync.reload({
      stream: true
    }))
});