gulp配置实现修改js、css、html自动刷新

写在前面：

本配置支持es6、less

1.首先

给出初始的目录结构

给出执行gulp后的目录结构

给出执行gulp --p后的目录结构

2.package.json里是一个写入。文件描述了npm包的相关配置信息（作者、简介、包依赖等）和所需模块。

{
  "name": "gruntTest",
  "version": "1.0.0",
  "description": "",
  "main": "Gulpfile.js"
}

3.Gulpfile.js添加要执行的任务

var gulp = require(‘gulp‘);
var uglify = require(‘gulp-uglify‘);  //js压缩
var concat = require(‘gulp-concat‘);  //合并文件
var minifyCSS = require(‘gulp-minify-css‘);  //css压缩
var less = require(‘gulp-less‘);  //less
var changedInPlace = require(‘gulp-changed-in-place‘);//不管修改哪个文件，gulp会简化DEST里的html文件
var minifyHTML = require(‘gulp-htmlmin‘);  //简化html
var browserSync = require(‘browser-sync‘).create(); //自动刷新
var babel = require(‘gulp-babel‘); //支持es6
var argv = require(‘yargs‘).argv; //支持不同环境
var sequence = require(‘gulp-sequence‘); //按照顺序执行
var watch = require(‘watch‘);  //监听
var clean = require(‘gulp-clean‘);  //监听
//npm install --save-dev gulp-babel babel-preset-es2015
var DEST = ‘dest/‘;
var HTML_PATH = ‘./src/*.html‘;

gulp.task(‘minify-js‘, function(){
	if(argv.p){
		gulp.src(‘src/source/*.js‘)
			.pipe(babel({
				presets: [‘es2015‘]
			}))
			.pipe(uglify())
			.pipe(concat(‘gruntTest.min.js‘))
			.pipe(gulp.dest(DEST+‘js‘))

	}else{
		gulp.src(‘src/source/*.js‘)
			.pipe(babel({
				presets: [‘es2015‘]
			}))
			.pipe(uglify())
			.pipe(concat(‘gruntTest.min.js‘))
			.pipe(gulp.dest(‘src/js‘))
	}
});
gulp.task(‘minify-css‘, function(){
	if(argv.p){
		gulp.src(‘src/less/*.less‘)  //或者用[‘src/less/p1.less‘,‘src/less/p2.less‘]
			.pipe(less())
			.pipe(minifyCSS())
			.pipe(concat(‘style.min.css‘))
			.pipe(gulp.dest(DEST+‘css‘))
			.pipe(browserSync.stream());
		}else{
			gulp.src(‘src/less/*.less‘)  //或者用[‘src/less/p1.less‘,‘src/less/p2.less‘]
				.pipe(less())
				.pipe(minifyCSS())
				.pipe(concat(‘style.min.css‘))
				.pipe(gulp.dest(‘src/css‘))
				.pipe(browserSync.stream());
		}
});
gulp.task(‘minify-html‘, function(){
	gulp.src(HTML_PATH)
		.pipe(changedInPlace({firstPass: true}))
		.pipe(minifyHTML({collapseWhitespace: true}))
		.pipe(gulp.dest(DEST))
		.pipe(browserSync.stream());
});
gulp.task(‘clean‘, function () {
  	gulp.src([‘./src/css/*.css‘,‘./src/js/*.js‘], {read: false})
    	.pipe(clean());
});
var files = [
	‘./src/css/*.css‘,
	‘./src/js/*.js‘
];
gulp.task(‘browser-sync‘, function(){
	browserSync.init(files,{
		server: {
			baseDir: ‘./‘
		},
		port: 9999
	});
});
gulp.task(‘watch‘, function() {
	gulp.watch(‘./src/source/*.js‘,[‘minify-js‘]);
  	gulp.watch(‘./src/less/*.less‘,[‘minify-css‘]);
});
if(argv.p){
	//product
	gulp.task(‘default‘, sequence(‘minify-js‘,‘minify-css‘,‘minify-html‘,‘browser-sync‘));
}else{
	//develop
	gulp.task(‘default‘, sequence(‘clean‘,‘minify-js‘,‘minify-css‘,‘watch‘,‘browser-sync‘));
}

4.扩展

（1）上面一堆require看着好烦人，也很庞大。此处可以引入“gulp-load-plugins”插件

var gulpLoadPlugins = require(‘gulp-load-plugins‘),
      plugins = gulpLoadPlugins();

plugins.uglify();即可执行相应任务

（2）若某个文件夹下好多文件，那么watch监听时需要一一列举，可以目录写成json格式（例如src.source.*.js）。通过引入“fs”插件，用fs.freaddirSync()方法去读路径。循环即可，此处的实现纯属写js代码。