React Router with server rendering

{data ? (
  <script
    defer
    src={data.tracker.src}
    integrity={data.tracker.integrity}
    crossOrigin="anonymous"
    data-website-id={data.tracker.siteId}
  />
) : null}

// the tracker tag's attributes, read on the server for every request. they come
// from the same release manifest the snippet generator uses; react renders them
// as a script element, which is how a react router app carries the snippet.
import { releases, scriptUrl } from "tracker/snippet";

export type TrackerTag = { src: string; integrity: string; siteId: string };

function required(name: string): string {
  const value = process.env[name];
  if (!value) throw new Error(`missing env ${name}`);
  return value;
}

export function trackerTag(): TrackerTag {
  const version = required("SA_TRACKER_VERSION");
  const entry = releases().find((r) => r.version === version);
  if (!entry) throw new Error(`tracker version ${version} is not in the release manifest`);
  return {
    src: scriptUrl(required("SA_GATEWAY_ORIGIN"), version),
    integrity: entry.integrity,
    siteId: required("SA_SITE_ID"),
  };
}

<script defer src="https://in.analytics.example/v/1.1.0/sdk.js" integrity="sha384-lxlitLtIMAeT/K3ieev+MeMGxZe7oceuWLOy8GZAjK7TMKS2Uh9UPmfGLBczUPsq" crossorigin="anonymous" data-website-id="3f6a0c2e-9b1d-4e7a-8c5f-1d2e3f4a5b6c"></script>