// util1.js
export default {
  a:1 
}
// util2.js
export function f1(){}
export function f2(){}

// index.js
import obj from 'util1.js'
// 哪怕只引入一个也需要添加花括号
import { f1, f2 } from 'util2.js'

export var a =1;
export let myVar= 'sss';
export const MYVAR = 'ssss';
export function Myfunc(){
   ……
  }
export class myclass{
   ……
 }

const my_const ='ssss';
function my_func () {
.....
}
export { my_const, my_func}

//报错
export 1;
//报错
var m = 1;
export m;
//报错
function f () {}
export f ;
//正确
export function f (){};

import {test1, test2 } from './example.js'
import {test1} from './example.js'
import {test2} from './example.js'
import * as example from './example.js'

//第一组
export default function crc32 (){
 //...
}
import crc32 from'crc32'; //输入
//第二组
export function crc32(){//输出
//...
};
import {crc32} from'crc32';//输入

export a = 1
export default function () {}

// 默认值在前，使用逗号分隔
import sum, { a } from 'example.js'

// 重命名
export { test as name }
import{ name as name2 }from'./example.js'

// export.js
var name= 'test1'
function changeName (name) {
 name = name
}
export {name, changeName }
//import.js
import { name,changeName }from'./export.js'
console.log(name)//test1
changeName('test2')
console.log(name)//test2
name = 'test3'//报错

foo();
import { foo } from 'my_module';

npm install gulp -g 
npm install gulp --save-dev

// 引入gulp脚本
var gulp = require('gulp')
// 创建一个sayhi的任务
gulp.task('sayhi', ()=>{
  console.log('hi')
})

cnpm install babel-core babel-preset-es2015 --save-dev

touch .babelrc

注意是JSON格式
{
  "presets":["es2015"]
}

// 引入gulp脚本
import gulp from 'gulp'
// 创建一个sayhi的任务
gulp.task('sayhi', ()=>{
  console.log('hi')
})

gulp.task('task-name', ()=>{
  return gulp.src('source-files')
  .pipe(gulpPlugin())
  .pipe(gulp.dest('destination'))
})

cnpm install gulp-sass --save-dev

// app/sass/styles.scss
.testing {
  width: percentage(5/7)
}

import gulp from 'gulp'
import sass from 'gulp-sass'
gulp.task('css', ()=> {
  return gulp.src('app/css/styles.scss')
  .pipe(sass())
  .pipe(gulp.dest('app/css'))
})

gulp.task('sass', function() {
  return gulp.src('app/scss/**/*.scss') 
    .pipe(sass())
    .pipe(gulp.dest('app/css'))
})

gulp.watch('file-to-watch',['tasks', 'to', 'run'])

gulp.task('watch', ()=>{
  gulp.watch('app/**/*.scss',['css'])
})

npm install browser-sync --save-dev

import browserSync from 'browser-sync'
gulp.task('browserSync', ()=> {
  browserSync({
    server: {
      baseDir: 'app'
    }
  })
})

gulp.task('sass', function() {
  return gulp.src('app/scss/**/*.scss') // Gets all files ending with .scss in app/scss
    .pipe(sass())
    .pipe(gulp.dest('app/css'))
    .pipe(browserSync.reload({
      stream: true
    }))
});

gulp.task('watch', ['array', 'of', 'tasks', 'to', 'complete','before', 'watch'], function (){
  // ...
})

gulp.task('watch', ['browserSync', 'sass'], function (){
  gulp.watch('app/scss/**/*.scss', ['sass']);
  // Other watchers
})

<!-- build:<type> <path> -->
... HTML Markup, list of script / link tags.
<!-- endbuild -->

<!--build:js js/main.min.js -->
<script src="js/lib/a-library.js"></script>
<script src="js/lib/another-library.js"></script>
<script src="js/main.js"></script>
<!-- endbuild -->

npm install gulp-useref --save-dev

var useref = require('gulp-useref');

gulp.task('useref', function(){

  return gulp.src('app/*.html')
        .pipe(useref())
        .pipe(gulp.dest('dist'));
});

npm install gulp-uglify --save-dev

// Other requires...
var uglify = require('gulp-uglify');
gulp.task('useref', function(){
  return gulp.src('app/*.html')
    .pipe(uglify()) // Uglifies Javascript files
    .pipe(useref())
    .pipe(gulp.dest('dist'))
});

npm install gulp-if gulp-minify-css --save-dev

var gulpIf = require('gulp-if');
var minifyCSS = require('gulp-minify-css');

gulp.task('useref', function(){

  return gulp.src('app/*.html')
    // Minifies only if it's a CSS file
    .pipe(gulpIf('*.css', minifyCSS()))
    // Uglifies only if it's a Javascript file
    .pipe(gulpIf('*.js', uglify()))
    .pipe(useref())
    .pipe(gulp.dest('dist'))
});

npm install gulp-imagemin --save-dev

var imagemin = require('gulp-imagemin');
gulp.task('images', function(){
  return gulp.src('app/images/**/*.+(png|jpg|gif|svg)')
  .pipe(imagemin())
  .pipe(gulp.dest('dist/images'))
});

npm install del --save-dev

var del = require('del');
gulp.task('clean', function() {
  del('dist');
});

gulp.task('clean:dist', function(callback){
  del(['dist/**/*', '!dist/images', '!dist/images/**/*'], callback)
});

gulp.task('build', [`clean`, `sass`, `useref`, `images`, `fonts`], function (){
  console.log('Building files');
})

var runSequence = require('run-sequence');

gulp.task('task-name', function(callback) {
  runSequence('task-one', 'task-two', 'task-three', callback);
});

gulp.task('task-name', function(callback) {
  runSequence('task-one', ['tasks','two','run','in','parallel'], 'task-three', callback);
});

gulp.task('build', function (callback) {
  runSequence('clean:dist',
    ['sass', 'useref', 'images', 'fonts'],
    callback
  )
})

-- es6-gulp     项目的根目录
    -- app      前端业务代码
        -- js
            -- class 类目录
                -- index 
        -- css 
        -- views  模板目录
            -- error.ejs
            -- index.ejs (ejs)
    -- server   服务器代码
        -- 使用express来创建
    -- tasks    自动化构建工具
        -- util
             -- args

import yargs from 'yargs'

const args = yargs
		// 命令行中是否有production参数 区分是否是开发环境
		.options('production', {
			boolean: true,
			default: false,
			describe: ' '
		})
		// 是否监听文件
		.options('watch', {
			boolean: true,
			default: false,
			describe: ''
		})
		// will autoly create the log files
		.options('verbose',{
			boolean: true,
			default: false,
			describe: ''
		})
		.options('sourcemaps',{
			describe:'force the creation of sourcemap'
		})
		.options('port',{
			string: true,
			default: 8080,
			describe: "watch the port"
		})
		.argv

gulp.task('scripts', ()=>{
	// gulp.src是打开目录的文件
	return gulp.src(['app/js/index.js'])
		//  处理错误逻辑，集中处理错误
		.pipe(plumber({
			errorHandle: function(){

			}
		}))
		// 对文件重新命名
		.pipe(named())
		// 进行编译, 借助webpack的功能gulpwebpack, webpack - module - loaders
		.pipe(gulpwebpack({
			module:{
				loaders:[
						{
							test: /\.js$/,
							loader: 'babel'
						}
						],
			}
		}), null, (err, stats) => {
			log('finished ')
		})
		// 编译完了放在哪里 gulp.dest()api 放在server里面
		.pipe(gulp.dest('server/publick/js'))
		// 混淆压缩,先拷贝一份重命名
		.pipe(rename({
			basename: 'cp',
			extname: '.min.js'
		}))
		.pipe(uglify(
				{
					compress:{properties: false},
					output:{'quoto_keys': true}
				}
				))
		.pipe(gulp.dest('server/public/js'))
		// 监听热更新
		.pipe(gulpif(args.watch, livereload()))
	
})

import gulp from 'gulp'
import gulpif from 'gulp-if'
import livereload from 'gulp-livereload'
import args from './util/args'

gulp.task('pages', ()=>{
	// 监听app 目录下的所有的ejs
	return gulp.src('app/**/*.ejs')
			// 拷贝到 server的目录下
			.pipe.dest('server')
			// 热更新
			.pipe(gulpif(args.watch, livereload()))
})

import gulp from 'gulp'
import gulpif from 'gulp-if'
import livereload from 'gulp-livereload'
import args from './util/args'

gulp.task('css', () => {
	return gulp.src('app/**/*.css')
			.pipe(gulp.dest('server/public'))
})

import gulp from 'gulp'
import gulpif from 'gulp-if'
// 启动服务器
import liveserver from 'gulp-live-server'

import args from './util/args'

gulp.task('server',()=> {
	if(!args.watch) return cb()
	// 创建一个服务器
	var server = liveserver.new(['--harmony','server/bin/www'])
	server.start()
	
//	实现浏览器的自动刷新
	gulp.watch(['server/public/**/*.js', 'server/views/**/*.ejs'], function (file) {
		// 通知服务器做响应的改变
		server.notify.apply(server, [file])
	})
	
	gulp.watch(['server/routes/**/*.js','server/app.js'], function () {
		server.start.bind(server)()
	})
})

import gulp from 'gulp'
import gulpif from 'gulp-if'
import gutil from 'gulp-util'
import args from './util/args'

gulp.task('browser', (cb) => {
	if(!args.watch) return cb()
	// 第一个参数指定监听的目录，第二个参数指定执行的脚本
	gulp.watch('app/**/*.js', ['scripts'])
	gulp.watch('app/**/*.css', ['css'])
	gulp.watch('app/**/*.ejs', ['pages'])
	
})

import gulp from 'gulp'
import args from './util/args'
import def from 'del'

gulp.task('clean', ()=>{
	return del(['server/public','server/views'])
	
})

import gulp from 'gulp'
import gulpSequence from 'gulp-sequence'

// serve 一定要放在最后面
gulp.task('build', gulpSequence('clean','css','pages','scripts',['browser','serve']))

import gulp from 'gulp'

gulp.task('default', ['build'])