gatsby-ssr.js

import React from "react";

exports.onRenderBody = ({ setHeadComponents }) => {
  const script = `(function(d) {
    var config = {
      kitId: 'txh3mim',
      scriptTimeout: 3000,
      async: true
    },
    h=d.documentElement,t=setTimeout(function(){h.className=h.className.replace(/\bwf-loading\b/g,"")+" wf-inactive";},config.scriptTimeout),tk=d.createElement("script"),f=false,s=d.getElementsByTagName("script")[0],a;h.className+=" wf-loading";tk.src='https://use.typekit.net/'+config.kitId+'.js';tk.async=true;tk.onload=tk.onreadystatechange=function(){a=this.readyState;if(f||a&&a!="complete"&&a!="loaded")return;f=true;clearTimeout(t);try{Typekit.load(config)}catch(e){}};s.parentNode.insertBefore(tk,s)
  })(document);`;

  setHeadComponents([
    <script
      key={"typekit-txh3mim"}
      dangerouslySetInnerHTML={{ __html: script }}
    />
  ]);
};