betterpenthouse/lib/browser-sandbox/replacePageCss.js

Generate critical path CSS for web pages

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = replacePageCss;

function replacePageCss({
  css
}) {
  console.log('debug: replacePageCss');

  function removeStyles() {
    var styleElements = document.querySelectorAll('link[rel="stylesheet"], style');
    Array.prototype.forEach.call(styleElements, function (element) {
      element.parentNode.removeChild(element);
    });
  }

  function insertStyles(styles) {
    var styleTag = document.createElement('style');
    styleTag.type = 'text/css'; // inject defaultWhiteBg to match before-render

    styles = 'body { background: #fff }' + styles; // if unreachable font-face src url in styles, phantomjs seems to crash here on Ubuntu :/

    styleTag.appendChild(document.createTextNode(styles));
    document.head.appendChild(styleTag);
  }

  removeStyles();
  console.log('debug: removed styles');
  insertStyles(css);
}