gulpfile.js

'use strict';
 
var gulp = require('gulp');
var sass = require('gulp-sass');
var sourcemaps = require('gulp-sourcemaps');
var autoprefixer = require('gulp-autoprefixer');

var input  = './scss/**/*.scss';
var output = './';
var sassOptions = {
  errLogToConsole: true,
  outputStyle: 'expanded'
};

gulp.task('sass', function () {
  return gulp
    // Find all `.scss` files from the `stylesheets/` folder
    .src(input)
    .pipe(sourcemaps.init())
    // Run Sass on those files
    .pipe(sass(sassOptions).on('error', sass.logError))
    .pipe(sourcemaps.write(output))
    .pipe(autoprefixer())
    // Write the resulting CSS in the output folder
    .pipe(gulp.dest(output));
});

gulp.task('watch', function() {
  return gulp
    // Watch the input folder for change,
    // and run `sass` task when something happens
    .watch(input, ['sass'])
    // When there is a change,
    // log a message in the console
    .on('change', function(event) {
      console.log('File ' + event.path + ' was ' + event.type + ', running tasks...');
    });
});

gulp.task('default', ['sass', 'watch' /*, possible other tasks... */]);