Simple gulpfile that process, lints and minify scss to css and js files. It also keeps files cached in order to improve tasks execution time.

gulpfile.js

var autoprefixer = require('gulp-autoprefixer');
var cache = require('gulp-cached');
var cleanCSS = require('gulp-clean-css');
var concat = require('gulp-concat');
var eslint = require('gulp-eslint');
var gulp = require('gulp');
var notify = require("gulp-notify");
var plumber = require('gulp-plumber');
var remember = require('gulp-remember');
var sass = require('gulp-sass');
var sassLint = require('gulp-sass-lint');
var sourcemaps = require('gulp-sourcemaps');
var uglify = require('gulp-uglify');

var csspath = {
    src: 'src/sass/**/*.scss',
    dest: 'css/'
};

var jspath = {
    src: ['src/js/**/*.js', '!src/js/**/*.min.js'],
    dest: 'js/'
};

//compiling scss files
gulp.task("sass", function () {
    return gulp.src(csspath.src)
        .pipe(plumber({ errorHandler: handleErrors }))
        .pipe(cache('sass')) // cache all files, so it'll process only changed files
        .pipe(sassLint())
        .pipe(sassLint.format())
        .pipe(sassLint.failOnError())
        // .pipe(sourcemaps.init())
        .pipe(sass({
            onError: function (err) {
                return notify().write(err);
            }
        }))
        .pipe(autoprefixer({ browsers: ['last 2 version', 'safari 5', 'ie >= 9'] }))
        .pipe(cleanCSS())
        // .pipe(sourcemaps.write('.'))
        .pipe(remember('sass')) // now I don't need just the changed files but all the styles, so I can concat'em:
        .pipe(concat('styles.css'))
        .pipe(gulp.dest(csspath.dest))
        .pipe(notify({
            message: 'SCSS complete'
        }));
});


gulp.task('processjs', function () {
    gulp.src(jspath.src)
        .pipe(plumber({ errorHandler: handleErrors }))
        .pipe(cache('compressing-js')) // cache all files, so it'll process only changed files
        .pipe(eslint({
            rules: {},
            globals: ['jQuery', '$', '$$'],
            envs: ['browser']
        }))
        .pipe(eslint.format())
        .pipe(eslint.failAfterError())
        .pipe(uglify())
        .pipe(gulp.dest(jspath.dest))
        .pipe(notify({
            message: 'processjs complete'
        }));
});


//Watch task
gulp.task("watch", function () {
    gulp.start('sass');
    gulp.start('processjs');
    gulp.watch(csspath.src, ['sass']);
    gulp.watch(jspath.src, ['processjs']);
});

/**
 * Handle errors.
 */
function handleErrors() {
    var args = Array.prototype.slice.call(arguments);
    notify.onError({
        title: 'Task Failed [<%= error.message %>',
        message: 'See console.',
        sound: 'Sosumi'
    }).apply(this, args);
    this.emit('end');
}