gulp插件：gulp-cssnano，gulp-minify-css 和gulp-clean-css

近日在学习《Web前端自动化构建》，关于gulp的css压缩插件，书中先后提到了两个，分别是gulp-cssnano和gulp-minify-css，而执行npm install gulp-minify-css –save-dev时，控制台提示如下：
npm WARN deprecated gulp-minify-css@1.2.4: Please use gulp-clean-css
gulp-minify-css@1.2.4
至此，一共出现了三个压缩css的gulp插件。

对比如下

压缩能力：

相同css文件分别用这三个插件进行压缩，

• gulp-cssnano：2.55KB；
• gulp-minify-css: 2.44KB;
• gulp-clean-css: 2.55KB;

维护：

• gulp-cssnano： current tags: 2.1.3 Published 4 months ago；
  附npm地址：https://www.npmjs.com/package/gulp-cssnano
• gulp-minify-css: 1.2.4 Published 2 years ago Please use gulp-clean-css;
  附npm地址：https://www.npmjs.com/package/gulp-minify-css
• gulp-clean-css: 3.9.4 Published 2 months ago ;
  附npm地址：https://www.npmjs.com/package/gulp-clean-css

使用：

鉴于gulp-minify-css已被废弃，在此仅对比gulp-cssnano和gulp-clean-css
gulp-cssnano
安装：

npm install gulp-cssnano --save-dev

示例：

const gulp = require('gulp');
const cssnano = require('gulp-cssnano');

gulp.task('styles', () => {
    return gulp.src('./main.css')
        .pipe(cssnano())
        .pipe(gulp.dest('dist'));
});

Source Maps:

const gulp = require('gulp');
const cssnano = require('gulp-cssnano');
const sourcemaps = require('gulp-sourcemaps');

gulp.task('styles', () => {
    return gulp.src('main.css')
        .pipe(sourcemaps.init())
        .pipe(cssnano())
        .pipe(sourcemaps.write('.'))
        .pipe(gulp.dest('dist'));
});

---

gulp-clean-css
安装：

npm install gulp-clean-css --save-dev

示例：

const gulp = require('gulp');
const cleanCSS = require('gulp-clean-css');

gulp.task('minify-css', () => {
  return gulp.src('styles/*.css')
    .pipe(cleanCSS({compatibility: 'ie8'}))
    .pipe(gulp.dest('dist'));
});

gulp-clean-css支持回调函数

const gulp = require('gulp');
const cleanCSS = require('gulp-clean-css');

gulp.task('minify-css', () => {
  return gulp.src('styles/*.css')
    .pipe(cleanCSS({debug: true}, (details) => {
      console.log(`${details.name}: ${details.stats.originalSize}`);
      console.log(`${details.name}: ${details.stats.minifiedSize}`);
    }))
  .pipe(gulp.dest('dist'));
});

示例代码中可以获取css压缩前后的stats信息，同时它也提供了file name以及path用于其他分析。
Source Maps:

const gulp = require('gulp');
const cleanCSS = require('gulp-clean-css');
const sourcemaps = require('gulp-sourcemaps');

gulp.task('minify-css',() => {
  return gulp.src('./src/*.css')
    .pipe(sourcemaps.init())
    .pipe(cleanCSS())
    .pipe(sourcemaps.write())
    .pipe(gulp.dest('dist'));
});