proginn-frontend/plugins/replace-html-styles/index.js

function ReplaceHtmlStyles() {
  this.replace = function(htmlPluginData, callback) {
    //console.log(htmlPluginData);
    let html = htmlPluginData.html;
    //     //console.log(html);
    let htmlRegx = new RegExp("\\<style[^\\>]*\\>.*?\\<\\/style\\>", "g");
    let match = html.match(htmlRegx);
    if (match) {
      //console.log(match)
      html = html.replace(htmlRegx, "");
      //console.log(html)
      match.forEach((item, index) => {
        html = html.replace(/<\/body>/, item + "</body>");
      });
      htmlPluginData.html = html;
    }

    callback(null, htmlPluginData);
  };
}

ReplaceHtmlStyles.prototype.apply = function(compiler) {
  if (compiler.hooks) {
    compiler.hooks.compilation.tap("ReplaceHtmlStyles", compilation => {
      if (compilation.hooks.htmlWebpackPluginAfterHtmlProcessing) {
        compilation.hooks.htmlWebpackPluginAfterHtmlProcessing.tapAsync(
          "ReplaceHtmlStyles",
          this.replace
        );
      } else {
        var HtmlWebpackPlugin = require("html-webpack-plugin");

        if (!HtmlWebpackPlugin) {
          throw new Error(
            "Please ensure that `html-webpack-plugin` was placed before `replace-html-styles` in your Webpack config if you were working with Webpack 4.x!"
          );
        }

        HtmlWebpackPlugin.getHooks(compilation).beforeEmit.tapAsync(
          "ReplaceHtmlStyles",
          this.replace
        );
      }
    });
  } else {
    compiler.plugin("compilation", compilation => {
      compilation.plugin("html-webpack-plugin-beforeEmit", this.replace);
    });
  }
};

module.exports = ReplaceHtmlStyles;