1、以1920* 1080的设计稿为例，实现PC端不同分辨率适配
2、安装依赖
npm install --save lib-flexible 或者 yarn addlib-flexible -save
npm installpx2rem-loader -D或者 yarn addpx2rem-loader
npm 安装不上时可以用cnpm
3、在utils文件下新建 一个 js 文件 如viewport.js 代码如下
(function() {var cssText ='' +'@charset "utf-8";html{color:#000;background:#fff;-webkit-text-size-adjust:100%;-ms-text-size-adjust:100%;-webkit-overflow-scrolling:touch}html *{outline:0;-webkit-text-size-adjust:none;-webkit-tap-highlight-color:transparent}body,html{font-family:"Microsoft YaHei",sans-serif,Tahoma,Arial}article,aside,blockquote,body,button,code,dd,details,div,dl,dt,fieldset,figcaption,figure,footer,form,h1,h2,h3,h4,h5,h6,header,hgroup,hr,input,legend,li,menu,nav,ol,p,pre,section,td,textarea,th,ul{margin:0;padding:0;-webkit-box-sizing:border-box;-moz-box-sizing:border-box;box-sizing:border-box}article,aside,details,figcaption,figure,footer,header,hgroup,menu,nav,section{display:block}input,input[type=button],input[type=reset],input[type=submit]{resize:none;border:none;-webkit-appearance:none;border-radius:0}input,select,textarea{font-size:100%}table{border-collapse:collapse;border-spacing:0}fieldset,img{border:0}abbr,acronym{border:0;font-variant:normal}del{text-decoration:line-through}address,caption,cite,code,dfn,em,th,var{font-style:normal;font-weight:500}ol,ul{list-style:none}caption,th{text-align:left}h1,h2,h3,h4,h5,h6{font-size:100%;font-weight:500}q:after,q:before{content:\'\'}sub,sup{font-size:75%;line-height:0;position:relative;vertical-align:baseline}sup{top:-.5em}sub{bottom:-.25em}a:hover{text-decoration:underline}a,ins{text-decoration:none}a:active,a:hover,a:link,a:visited{background:0 0;-webkit-tap-highlight-color:transparent;-webkit-tap-highlight-color:transparent;outline:0;text-decoration:none}';// cssText endvar styleEl = document.createElement('style');document.getElementsByTagName('head')[0].appendChild(styleEl);if (styleEl.styleSheet) {if (!styleEl.styleSheet.disabled) {styleEl.styleSheet.cssText = cssText;}} else {try {styleEl.innerHTML = cssText;} catch (e) {styleEl.innerText = cssText;}}})();;(function(win, lib) {var doc = win.document;var docEl = doc.documentElement;var metaEl = doc.querySelector('meta[name="viewport"]');var flexibleEl = doc.querySelector('meta[name="flexible"]');var dpr = 0;var scale = 0;var tid;var flexible = lib.flexible || (lib.flexible = {});if (metaEl) {console.warn('将根据已有的meta标签来设置缩放比例');var match = metaEl.getAttribute('content').match(/initial\-scale=([\d\.]+)/);if (match) {scale = parseFloat(match[1]);dpr = parseInt(1 / scale);}} else if (flexibleEl) {var content = flexibleEl.getAttribute('content');if (content) {var initialDpr = content.match(/initial\-dpr=([\d\.]+)/);var maximumDpr = content.match(/maximum\-dpr=([\d\.]+)/);if (initialDpr) {dpr = parseFloat(initialDpr[1]);scale = parseFloat((1 / dpr).toFixed(2));}if (maximumDpr) {dpr = parseFloat(maximumDpr[1]);scale = parseFloat((1 / dpr).toFixed(2));}}}if (!dpr && !scale) {var isAndroid = win.navigator.appVersion.match(/android/gi);var isIPhone = win.navigator.appVersion.match(/iphone/gi);var devicePixelRatio = win.devicePixelRatio;if (isIPhone) {// iOS下，对于2和3的屏，用2倍的方案，其余的用1倍方案if (devicePixelRatio >= 3 && (!dpr || dpr >= 3)) {dpr = 3;} else if (devicePixelRatio >= 2 && (!dpr || dpr >= 2)) {dpr = 2;} else {dpr = 1;}} else {// 其他设备下，仍旧使用1倍的方案dpr = 1;}scale = 1 / dpr;}docEl.setAttribute('data-dpr', dpr);if (!metaEl) {metaEl = doc.createElement('meta');metaEl.setAttribute('name', 'viewport');metaEl.setAttribute('content', 'initial-scale=' + scale + ', maximum-scale=' + scale + ', minimum-scale=' + scale + ', user-scalable=no');if (docEl.firstElementChild) {docEl.firstElementChild.appendChild(metaEl);} else {var wrap = doc.createElement('div');wrap.appendChild(metaEl);doc.write(wrap.innerHTML);}}function refreshRem() {var width = docEl.getBoundingClientRect().width;if (width / dpr > 540) {width = width * dpr;}var rem = width / 10;docEl.style.fontSize = rem + 'px';flexible.rem = win.rem = rem;}win.addEventListener('resize', function() {clearTimeout(tid);tid = setTimeout(refreshRem, 300);}, false);win.addEventListener('pageshow', function(e) {if (e.persisted) {clearTimeout(tid);tid = setTimeout(refreshRem, 300);}}, false);if (doc.readyState === 'complete') {doc.body.style.fontSize = 12 * dpr + 'px';} else {doc.addEventListener('DOMContentLoaded', function(e) {doc.body.style.fontSize = 12 * dpr + 'px';}, false);}refreshRem();flexible.dpr = win.dpr = dpr;flexible.refreshRem = refreshRem;flexible.rem2px = function(d) {var val = parseFloat(d) * this.rem;if (typeof d === 'string' && d.match(/rem$/)) {val += 'px';}return val;}flexible.px2rem = function(d) {var val = parseFloat(d) / this.rem;if (typeof d === 'string' && d.match(/px$/)) {val += 'rem';}return val;}})(window, window['lib'] || (window['lib'] = {}));
4、在 main.js 引入viewport.js
5、修改build中的配置文件 utils.js ，加入以下代码
constpx2remLoader={
loader:"px2rem-loader",
options:{
//这个参数是通过psd设计稿的宽度/10来计算,这里以1920为标准
remUnit:192
}
};
6、修改generateLoaders 方法中的loaders 如下：
constloaders=options.usePostCSS
?[cssLoader,postcssLoader,px2remLoader]
:[cssLoader,px2remLoader];
7、完成以上六步以后就可以按照设计图1:1开发了，单位仍然用px，例如：
温馨提示：
1、css不能写在行内，行内样式不能转为rem
2、背景图片background-size为 auto 不能自适应
3、修改完以后需要重新启动项目
