gulpfile.js

var gulp = require('gulp'),
	jshint = require('gulp-jshint'),
	uglify = require('gulp-uglify'),
	rename = require('gulp-rename'),
	concat = require('gulp-concat'),
	notify = require('gulp-notify'),
	cache = require('gulp-cache'),
// Requires the gulp-sass plugin
	sass = require('gulp-sass'),
	cssnano = require('gulp-cssnano');

gulp.task('sass', function(){
  return gulp.src('public/css/*.scss')
    .pipe(sass()) // Converts Sass to CSS with gulp-sass
	.pipe(cssnano())
    .pipe(gulp.dest('wp-content/themes/onerooftop/assets/css'))
    .pipe(notify({ message: 'Styles task complete' }))
});


// Concatenate & Minify JS
gulp.task('scripts', function() {
	return gulp.src('public/js/*.js')
		.pipe(concat('site.js'))
		.pipe(gulp.dest('dist'))
		.pipe(rename('site.min.js'))
		.pipe(uglify())
		.pipe(gulp.dest('dist'));
});

// gulp.task('minifiedcss', function(){
// 	return gulp.src('public/css/*.css')
// 	.pipe(cssnano())
// 	.pipe(gulp.dest('public/css/styles.min.css'))
// })

gulp.task('watch', function(){
	// gulp.watch('public/css/*.scss', ['sass']);
	//Js watch
	gulp.watch('public/js/*.js', ['scripts']);
});

package.json

{
  "name": "onerooftop",
  "version": "0.0.0",
  "description": "Free Kids ID",
  "main": "public.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "Mahbubur Rahman",
  "license": "BSD-2",
  "devDependencies": {
    "gulp": "~3.9.1",
    "gulp-sass": "^3.1.0",
    "gulp-cache": "~0.2.4",
    "gulp-concat": "~2.4.2",
    "gulp-jshint": "~1.9.0",
    "gulp-notify": "~2.0.1",
    "gulp-rename": "~1.2.0",
    "gulp-uglify": "~1.0.1"
  }
}