postcss使用

"devDependencies": {
    "autoprefixer": "^7.1.1",
    "browser-sync": "^2.18.8",
    "compass": "^0.1.1",
    "gulp": "^3.9.1",
    "gulp-changed": "^2.0.0",
    "gulp-compass": "^2.1.0",
    "gulp-html-beautify": "^1.0.1",
    "gulp-load-plugins": "^1.5.0",
    "gulp-plumber": "^1.1.0",
    "gulp-postcss": "^7.0.0",
    "gulp-pug": "^3.3.0",
    "gulp-sass": "^3.1.0",
    "gulp-sourcemaps": "^2.6.0",
    "precss": "^1.4.0",
    "pug": "^2.0.0-beta.12",
    "cssgrace": "^3.0.0"
  },
  "dependencies": {
    "express": "^4.15.2",
    "pug": "^2.0.0-beta.12"
  }

var gulp        = require("gulp");
var plugins     = require("gulp-load-plugins")();
var browserSync = require("browser-sync").create();
var postcss     = require(‘gulp-postcss‘);
var sourcemaps  = require(‘gulp-sourcemaps‘);
var cssgrace    = require(‘cssgrace‘);
// /*执行命令行工具*/
// var exec = require(‘child_process‘).exec;
// exec("node server/index.js", function(err, stdout, stderr) {
//     var status = err ? -1 : 1,
//         cmd_result = err ? stderr : stdout;
//     // 可以获取到错误信息、标准输出和标准错误输出，接下来继续处理吧
// });

//编译pug
gulp.task("pug:compile",function() {
	gulp.src("src/*.pug")
	.pipe(plugins.plumber())
	.pipe(plugins.changed("./build/",{extension:".html"}))
	.pipe(plugins.pug({
		pretty:"\t"
	}))
	.pipe(plugins.htmlBeautify({
		indent_size:4,
		indent_char:" "
	}))
	.pipe(gulp.dest("./build/"))
})
//监控pug
gulp.task("pug:watch",function() {
	gulp.watch("src/*.pug",["pug:compile"])
})
//编译pug-templates
gulp.task(‘pug-templates:compile‘,function(){
    gulp.src(‘src/*.pug‘)
    .pipe(plugins.plumber())
    .pipe(plugins.pug({
        pretty: ‘\t‘
    }))
    .pipe(plugins.htmlBeautify({
        indent_size: 4,
        indent_char: ‘ ‘,
        unformatted: true,
        extra_liners: []
    }))
    .pipe(gulp.dest(‘./build/‘));
});
//监控pug-templates
gulp.task(‘pug-templates:watch‘,function(){
   gulp.watch(‘src/templates/*.pug‘,[‘pug-templates:compile‘]);
});

/*编译compass*/
gulp.task("compass:compile",function() {
	gulp.src("src/sass/sass_parts/*.scss")
	.pipe(plugins.plumber())
	.pipe(plugins.compass({
		config_file:"./src/sass/config.rb",
		sass:"src/sass/sass_parts",
		css:"src/sass/stylesheets"
	}))
	.pipe(sourcemaps.init())
	.pipe( postcss([ require(‘precss‘), require(‘autoprefixer‘), cssgrace ]) )
    .pipe( sourcemaps.write(‘.‘) )
	.pipe(gulp.dest("./build/css"));
})
//监控compass sass
gulp.task("compass:watch",function() {
	gulp.watch("src/sass/sass_parts/**/*.scss",["compass:compile"]);
});
//browser-sync
gulp.task("browser-sync",function() {
	var files = [
	"./build/*.html",
	"./build/**/*.css",
	"./build/**/*.js"
	];
	browserSync.init(files,{
		server:{
			baseDir:"./build"
		},
		port:3061
	})
})
gulp.task("default",["pug:watch","pug-templates:watch","compass:watch","browser-sync"])