gulpfile.js

var gulp = require('gulp');
var sass = require('gulp-sass');
var shell = require('gulp-shell');


gulp.task('styles', function() {
  gulp.src('scss/**/*.scss')
    .pipe(sass().on('error', sass.logError))
    .pipe(gulp.dest('css/'));
});

//Watch task
gulp.task('default',function() {
  gulp.watch('scss/**/*.scss',['styles']);
});

// Clear all caches
gulp.task('clear-css-js-cache', shell.task([
  'drush cr all'
]));