gulpfile.js

var gulp = require('gulp'),
    minify = require('gulp-minify-css'),
    rename = require('gulp-rename'),
    sass = require('gulp-sass'),
    concat = require('gulp-concat'),
    sourcemaps = require('gulp-sourcemaps'),
    autoprefixer = require('gulp-autoprefixer');

var config = {
    publicDir: './src/main/webapp/static'
};

var sassSources = [
    './bower_components/bootstrap/scss/bootstrap.scss',
    './src/main/webapp/scss/style.scss'
];

var sassOptions = {
    errLogToConsole: true,
    outputStyle: 'expanded'
};

var jsSources = [
    './src/main/webapp/js/bootstrap/bootstrap.min.js',
    './src/main/webapp/js/bootstrap.file-input.js',
    './src/main/webapp/js/mr.js',
    './src/main/webapp/js/survey.js',
];

gulp.task('css', function() {
    return gulp.src(sassSources)
        .pipe(sourcemaps.init())
        .pipe(sass(sassOptions).on('error', sass.logError))
        .pipe(sourcemaps.write())
        .pipe(autoprefixer({
            browsers: ['last 2 versions'],
            cascade: false
        }))
        .pipe(concat('style.css'))
        .pipe(gulp.dest(config.publicDir + '/css'));
});

gulp.task('js', function() {
    gulp.src(jsSources)
        .pipe(concat('script.js'))
        .pipe(gulp.dest(config.publicDir + '/js'))
});

gulp.task('minify', ['css'], function() {
    return gulp.src(config.publicDir + '/css/*.css')
        .pipe(minify({ compatibility: 'ie8' }))
        .pipe(rename({ extname: '.min.cs' }))
        .pipe(gulp.dest(config.publicDir + '/css'));
});

gulp.task('default', ['css', 'js', 'minify'])