perf: cut cold route compilation and unblock preview images (#6441)

scripts/benchmarks/dev-benchmark-lib.spec.ts

@@ -0,0 +1,56 @@
+import { describe, expect, it } from "vitest";
+
+import {
+  countDuplicateTrpcPaths,
+  normalizeTrpcPath,
+  summarize,
+  validateBrowserMeasurement,
+} from "./dev-benchmark-lib.mts";
+
+describe("development benchmark measurements", () => {
+  it("preserves tRPC input payloads when counting duplicates", () => {
+    const first = "/api/trpc/board.get?batch=1&input=%7B%22json%22%3A1%7D";
+    const second = "/api/trpc/board.get?batch=1&input=%7B%22json%22%3A2%7D";
+
+    expect(normalizeTrpcPath(first)).toBe("/api/trpc/board.get?batch=1&input=%7B%22json%22%3A1%7D");
+    expect(countDuplicateTrpcPaths([first, second, first, "/api/trpc/user.get"])).toBe(1);
+  });
+
+  it("reports median, p95, deviation, and high outliers", () => {
+    expect(summarize([1, 2, 3, 4, 5, 6, 100])).toEqual({
+      count: 7,
+      min: 1,
+      median: 4,
+      p95: null,
+      max: 100,
+      standardDeviation: 34,
+      outliers: [100],
+    });
+  });
+
+  it("averages both middle values for an even sample count", () => {
+    expect(summarize([100, 200]).median).toBe(150);
+    expect(summarize(Array.from({ length: 20 }, (_, index) => index + 1)).p95).toBe(19);
+  });
+
+  it("requires a successful authenticated board hydration and interaction", () => {
+    expect(
+      validateBrowserMeasurement({
+        responseStatus: 307,
+        domContentLoadedMs: 120,
+        boardHydratedMs: null,
+        widgetsReadyMs: null,
+        widgetCount: 0,
+        coldImmediateInteractionMs: null,
+        postIdleWarmInteractionMs: null,
+      }),
+    ).toEqual([
+      "browser navigation returned HTTP 307",
+      "board hydration marker is missing",
+      "widget readiness marker is missing",
+      "representative board contains no widgets",
+      "cold immediate interaction timing is missing",
+      "post-idle warm interaction timing is missing",
+    ]);
+  });
+});