Why Does a Template Literal Cause Hydration Errors in React?

Below is one explanation that others have encountered with similar symptoms:

What's Happening

When you use a template literal like

JSCopied
{ name ? `${name} <${email}>` : email }

React ends up outputting a single text node whose content is built from the interpolation. In production, the server‐rendered output and the client’s render can sometimes end up with subtle differences (for example, in whitespace or escaping) when combining everything into one text node. This causes React’s hydration to fail—since React expects the server and client DOM to match exactly.

In contrast, when you split the text into multiple nodes

JSXCopied
{ name ? (
  <>
    {name}
    {" <"}
    {email}
    {">"}
  </>
) : (
  email
)}

each piece is its own text node. React can then reconcile them more reliably because there’s a clear separation of nodes and less opportunity for a mismatch in the internals of string interpolation.

Why It Only Happens in Production

Development mode uses extra warnings and “re-renders” that may mask these tiny differences. Production optimizations (like minification or even slight differences in how Babel transforms template literals) can introduce or reveal such mismatches. The fact that you’re using features like unstable_noStore() also means that the server rendering isn’t getting cached between requests, so any minor differences become more apparent.

What To Do

While it isn’t completely obvious why template literals would differ between the server and client in your particular setup, splitting the string into multiple text nodes or fragments (as you already discovered) sidesteps the issue. If you still want to use a template literal, try to verify that no extra whitespace or character escapes are introduced in your production build. For example, you might try to trim the output:

JSXCopied
{ name ? `${name.trim()} <${email.trim()}>` : email.trim() }

Sometimes even wrapping values in a String(...) or using a helper function to ensure consistency can help, but splitting up the text into explicit nodes is generally the safest workaround.

In Summary

The hydration error you see is most likely caused by a tiny discrepancy in the text content between the server-generated markup and what the client produces during hydration. Using multiple text nodes lets React reconcile the output more precisely, avoiding the mismatch that leads to hydration errors.

Let me know if you need further assistance with this Next.js hydration issue!