react: webpack手机适配

npm install -g create-react-app

npx create-react-app my-app

1.npm run  eject 

2.html计算

<script>
    !(function (win, doc) {
      function setFontSize() {
        var baseFontSize = 100;
        var baseWidth = 320;
        var clientWidth = document.documentElement.clientWidth || window.innerWidth;
        var innerWidth = Math.max(Math.min(clientWidth, 480), 320);
        var rem = 100;
        if (innerWidth > 362 && innerWidth <= 375) {
          rem = Math.floor(innerWidth / baseWidth * baseFontSize * 0.9);
        }
        if (innerWidth > 375) {
          rem = Math.floor(innerWidth / baseWidth * baseFontSize * 0.84);
        }
        window.__baseREM = rem;
        document.querySelector(‘html‘).style.fontSize = rem + ‘px‘;
      }
      var evt = ‘onorientationchange‘ in win ? ‘orientationchange‘ : ‘resize‘;
      var timer = null;
      win.addEventListener(evt, function () {
        clearTimeout(timer);
        timer = setTimeout(setFontSize, 300);
      }, false);
      win.addEventListener("pageshow", function (e) {
        if (e.persisted) {
          clearTimeout(timer);
          timer = setTimeout(setFontSize, 300);
        }
      }, false);
      setFontSize();
    }(window, document));
  </script>