yes, the worker has a pattern like this

<section>
<h2>Your IP Address: <span id="user-ip">Loading...</span></h2>
</section>

async function handleFetch(event) {
let ip = event.request.headers.get('cf-connecting-ip');
let customersIPsRangesJson = await $(cloudflare_kv_name).get('$(employee_ip_range_key)', 'json') || [];

const isIPInRange = customersIPsRangesJson.some(range => {
return range && range.includes('-') && checkIPInRange(ip, range);
});

if (isIPInRange) {
return fetch(event.request);
} else {
return handleEvent(event, ip);
}
}

class TextRewriter {
constructor(newText) {
this.newText = newText;
}

element(element) {
const newContent = <span id="user-ip">${this.newText}</span>;
element.replace(newContent, { html: true });
}
}

async function handleEvent(event, ip) {
try {
if (DEBUG) {
// customize caching
options.cacheControl = {
bypassCache: true,
};
}

const page = await getAssetFromKV(event, options);
const response = new Response(page.body, page);

// allow headers to be altered
response.headers.set("X-XSS-Protection", "1; mode=block");
response.headers.set("X-Content-Type-Options", "nosniff");
response.headers.set("X-Frame-Options", "DENY");
response.headers.set("Referrer-Policy", "unsafe-url");
response.headers.set("Feature-Policy", "none");

// Using HTMLRewriter to insert the IP address
const rewriter = new HTMLRewriter()
.on('span#user-ip', new TextRewriter(ip));

return rewriter.transform(response);
}

Route pattern must include zone name: example.org [code: 10022]