Name(&quot;head&quot;)[0].appendChild(style);
      return key;
    }

read: async (key) =&gt; {
      let style = document.createElement(&quot;style&quot;);
      style.type=&#39;text/css&#39;;
      let fontURI = testURI(&quot;resource&quot;, &quot;font&quot;, key);
      style.innerHTML = `@font-face {font-family: &quot;myFont&quot;; src: url(&quot;${fontURI}&quot;); } body { font-family: &quot;myFont&quot; }`;
      document.getElementsByTagName(&quot;head&quot;)[0].appendChild(style);
      await sleep