chore: import upstream snapshot with attribution

apps/webapp/app/routes/tests.sse.stream.ts

@@ -0,0 +1,67 @@
+import type { LoaderFunctionArgs } from "@remix-run/server-runtime";
+import { z } from "zod";
+import { logger } from "~/services/logger.server";
+import { sse } from "~/utils/sse.server";
+
+export async function loader({ request }: LoaderFunctionArgs) {
+  const url = new URL(request.url);
+  const searchParams = Object.fromEntries(url.searchParams.entries());
+
+  const options = z
+    .object({
+      minDelay: z.coerce.number().int(),
+      maxDelay: z.coerce.number().int(),
+      undefinedProbability: z.coerce.number().min(0).max(1).default(0.1),
+    })
+    .parse(searchParams);
+
+  logger.debug("Test SSE stream", { options });
+
+  let lastSignals = calculateChangeSignals(Date.now());
+
+  return sse({
+    request,
+    run: async (send, stop) => {
+      const result = await dateForUpdates(options);
+
+      if (!result) {
+        return stop();
+      }
+
+      const newSignals = calculateChangeSignals(result);
+
+      if (lastSignals.ts !== newSignals.ts) {
+        send({ data: JSON.stringify(newSignals) });
+      }
+
+      lastSignals = newSignals;
+    },
+  });
+}
+
+async function dateForUpdates(opts: {
+  minDelay: number;
+  maxDelay: number;
+  undefinedProbability: number;
+}): Promise<number | undefined> {
+  // Randomly await between minDelay and maxDelay
+  await new Promise((resolve) => {
+    setTimeout(resolve, Math.random() * (opts.maxDelay - opts.minDelay) + opts.minDelay);
+  });
+
+  // There should be about a x% chance that this returns undefined
+  if (Math.random() < opts.undefinedProbability) {
+    logger.debug("Test SSE dataForUpdates returning undefined");
+
+    return undefined;
+  }
+
+  // Randomly return true or false
+  return Date.now();
+}
+
+function calculateChangeSignals(ts: number) {
+  return {
+    ts,
+  };
+}