support encoding and decoding of invalid Date in turbo-stream

Author: rururux

integration/single-fetch-test.ts

@@ -170,6 +170,24 @@ const files = {
       )
     }
   `,
+
+  "app/routes/invalid-date.tsx": js`
+    import { useLoaderData, data } from "react-router";
+
+    export function loader({ request }) {
+      return data({ invalidDate: new Date("invalid") });
+    }
+
+    export default function InvalidDate() {
+      let data = useLoaderData();
+      return (
+        <>
+          <h1 id="heading">Invalid Date</h1>
+          <p id="date">{data.invalidDate.toISOString()}</p>
+        </>
+      )
+    }
+  `
 };
 
 test.describe("single-fetch", () => {
@@ -216,6 +234,23 @@ test.describe("single-fetch", () => {
         },
       },
     });
+
+    res = await fixture.requestSingleFetchData("/invalid-date.data");
+    expect(res.data).toEqual({
+      root: {
+        data: {
+          message: "ROOT",
+        },
+      },
+      "routes/invalid-date": {
+        data: {
+          invalidDate: expect.any(Date),
+        },
+      },
+    })
+
+    let date = (res.data as { ["routes/invalid-date"]: { data: { invalidDate: Date } } })["routes/invalid-date"].data.invalidDate
+    expect(isNaN(date.getTime())).toBe(true)
   });
 
   test("loads proper errors on single fetch loader requests", async () => {

packages/react-router/__tests__/vendor/turbo-stream-test.ts

@@ -50,6 +50,13 @@ test("should encode and decode Date", async () => {
   expect(output).toEqual(input);
 });
 
+test("should encode and decode invalid Date", async () => {
+  const input = new Date("invalid");
+  const output = await quickDecode(encode(input));
+  expect(isNaN(input.getTime())).toBe(true);
+  expect(isNaN(output.getTime())).toBe(true);
+});
+
 test("should encode and decode NaN", async () => {
   const input = NaN;
   const output = await quickDecode(encode(input));

packages/react-router/vendor/turbo-stream-v2/flatten.ts

@@ -106,7 +106,8 @@ function stringify(this: ThisEncode, input: unknown, index: number) {
                 (i in input ? flatten.call(this, input[i]) : HOLE);
             str[index] = `${result}]`;
           } else if (input instanceof Date) {
-            str[index] = `["${TYPE_DATE}",${input.getTime()}]`;
+            const dateTime = input.getTime();
+            str[index] = `["${TYPE_DATE}",${Number.isNaN(dateTime)? JSON.stringify("invalid") : dateTime}]`;
           } else if (input instanceof URL) {
             str[index] = `["${TYPE_URL}",${JSON.stringify(input.href)}]`;
           } else if (input instanceof RegExp) {