feat(javascript): retain queryable static route inventories (#6019)

src/domain/javascript/javascriptRouteResultBudget.test.ts

@@ -0,0 +1,63 @@
+import { expect, it } from "vitest";
+import { analyzeJavaScriptStaticSource } from "./javascriptStaticAnalysis.js";
+import { javaScriptRouteSourceFactsSchema } from "./javascriptRouteFacts.js";
+import { fitJavaScriptRouteSourceFacts } from "./javascriptRouteResultBudget.js";
+
+const facts = () =>
+  analyzeJavaScriptStaticSource(
+    `createBrowserRouter([{path:'/reports',children:[{path:'settings'},{path:'history'}]}]);`,
+  ).routes!;
+it("borrows complete source facts when the actual enclosing result has room", () => {
+  const input = facts();
+  expect(
+    fitJavaScriptRouteSourceFacts(
+      input,
+      Buffer.byteLength(JSON.stringify(input)),
+    ),
+  ).toBe(input);
+});
+it("preserves a bounded prefix with exact locations and explicit result capacity", () => {
+  const input = facts(),
+    original = JSON.stringify(input),
+    selected = fitJavaScriptRouteSourceFacts(input, 700)!;
+  expect(selected.candidates.length).toBeGreaterThan(0);
+  expect(selected.candidates.length).toBeLessThan(input.candidates.length);
+  expect(selected.candidates).toEqual(
+    input.candidates.slice(0, selected.candidates.length),
+  );
+  expect(selected.capacity).toEqual({
+    kind: "result-bytes",
+    limit_bytes: 700,
+    preceding_work_capacity: null,
+  });
+  expect(Buffer.byteLength(JSON.stringify(selected))).toBeLessThanOrEqual(700);
+  expect(JSON.stringify(input)).toBe(original);
+  expect(javaScriptRouteSourceFactsSchema.safeParse(selected).success).toBe(
+    true,
+  );
+});
+it("preserves earlier work capacity and uncertainty when transport admission also truncates", () => {
+  const input = facts();
+  input.capacity = {
+    kind: "route-work-or-facts",
+    limit_bytes: 4096,
+    accounted_fact_bytes: 2000,
+    accounted_work_bytes: 2000,
+  };
+  input.unresolved.push({
+    mechanism: "nested-route-object",
+    location: input.candidates[0]!.location,
+    reason: 'Unknown parent: "é💫"',
+  });
+  const selected = fitJavaScriptRouteSourceFacts(input, 800)!;
+  expect(selected.unresolved).toEqual(input.unresolved);
+  expect(selected.capacity).toMatchObject({
+    kind: "result-bytes",
+    preceding_work_capacity: input.capacity,
+  });
+  expect(Buffer.byteLength(JSON.stringify(selected))).toBeLessThanOrEqual(800);
+});
+it("omits an unmeasured facet when even its capacity envelope cannot fit", () => {
+  expect(fitJavaScriptRouteSourceFacts(facts(), 0)).toBeUndefined();
+  expect(fitJavaScriptRouteSourceFacts(facts(), 1)).toBeUndefined();
+});