gulp-postcss, autoprefixer, cssnano
const gulp = require('gulp');
const postcss = require('gulp-postcss');
const autoprefixer = require('autoprefixer');
const cssnano = require('cssnano');
function jsTask () {
return src("./src/css")
.pipe(sourcemaps.init())
.pipe(concat('style.css'))
.pipe(postcss([autoprefixer(), cssnano()]))
.pipe(sourcemaps.write('.'))
.pipe(dest('dist/css/'))
}