gulpfile.js

// https://gist.github.com/leymannx/f7867942184d01aa2311

var gulp = require('gulp'),
	sass = require('gulp-sass'),
	sassLint = require('gulp-sass-lint'),
	sourcemaps = require('gulp-sourcemaps'),
	prefix = require('gulp-autoprefixer');


// SETTINGS
// ---------------

var sassOptions = {
	outputStyle: 'expanded'
};


// BUILD SUBTASKS
// ---------------

gulp.task('styles', function () {
	return gulp.src('./assets/style/*.scss')
		.pipe(sourcemaps.init())
		.pipe(sass(sassOptions))
		.pipe(prefix())
		.pipe(sourcemaps.write('./'))
		.pipe(gulp.dest('./assets/style'));
});

gulp.task('sass-lint', function () {
	return gulp.src('assets/style/*.scss')
		.pipe(sassLint())
		.pipe(sassLint.format())
		.pipe(sassLint.failOnError());
});

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


// BUILD TASKS
// ------------

gulp.task('default', gulp.series('styles', 'watch'));
gulp.task('build', gulp.series('styles'));