Gulp file for CSS only

gulpfile.js

const gulp = require('gulp');
const sass = require('gulp-sass')(require('sass'));
const plumber = require('gulp-plumber');
const notify = require('gulp-notify');

function compileSass() {
	return gulp
		.src('src/assets/styles/*.scss')
		.pipe(
			plumber({
				errorHandler: notify.onError({
					title: 'Sass Compile Error',
					message: '<%= error.message %>'
				})
			})
		)
		.pipe(sass())
		.pipe(gulp.dest('src/assets/styles/'));
}

function watchSass() {
	gulp.watch('src/assets/styles/*.scss', compileSass);
}

gulp.task('sass', compileSass);
gulp.task('watch', watchSass);