Fetchers should persist data through reload/resubmit

.changeset/eighty-donkeys-run.md

@@ -0,0 +1,5 @@
+---
+"@remix-run/react": patch
+---
+
+Fetchers should persist data through reload/resubmit

integration/fetcher-test.ts

@@ -1,4 +1,4 @@
-import { test } from "@playwright/test";
+import { expect, test } from "@playwright/test";
 
 import { createAppFixture, createFixture, js } from "./helpers/create-fixture";
 import type { Fixture, AppFixture } from "./helpers/create-fixture";
@@ -143,6 +143,57 @@ test.describe("useFetcher", () => {
             );
           }
         `,
+
+        "app/routes/fetcher-echo.jsx": js`
+        import { json } from "@remix-run/node";
+        import { useFetcher } from "@remix-run/react";
+
+          export async function action({ request }) {
+            await new Promise(r => setTimeout(r, 1000));
+            let value = (await request.formData()).get('value');
+            return json({ data: "ACTION " + value })
+          }
+
+          export async function loader({ request }) {
+            await new Promise(r => setTimeout(r, 1000));
+            let value = new URL(request.url).searchParams.get('value');
+            return json({ data: "LOADER " + value })
+          }
+
+          export default function Index() {
+            let fetcherValues = [];
+            if (typeof window !== 'undefined') {
+              if (!window.fetcherValues) {
+                window.fetcherValues = [];
+              }
+              fetcherValues = window.fetcherValues
+            }
+
+            let fetcher = useFetcher();
+
+            let currentValue = fetcher.state + '/' + fetcher.data?.data;
+            if (fetcherValues[fetcherValues.length - 1] !== currentValue) {
+              fetcherValues.push(currentValue)
+            }
+
+            return (
+              <>
+                <input id="fetcher-input" name="value" />
+                <button id="fetcher-load" onClick={() => {
+                  let value = document.getElementById('fetcher-input').value;
+                  fetcher.load('/fetcher-echo?value=' + value)
+                }}>Load</button>
+                <button id="fetcher-submit" onClick={() => {
+                  let value = document.getElementById('fetcher-input').value;
+                  fetcher.submit({ value }, { method: 'post', action: '/fetcher-echo' })
+                }}>Submit</button>
+
+                {fetcher.state === 'idle' ? <p id="fetcher-idle">IDLE</p> : null}
+                <pre>{JSON.stringify(fetcherValues)}</pre>
+              </>
+            );
+          }
+        `,
       },
     });
 
@@ -232,4 +283,71 @@ test.describe("useFetcher", () => {
     await app.clickElement("#submit-index-post");
     await page.waitForSelector(`pre:has-text("${PARENT_INDEX_ACTION}")`);
   });
+
+  test("fetcher.load persists data through reloads", async ({ page }) => {
+    let app = new PlaywrightFixture(appFixture, page);
+
+    await app.goto("/fetcher-echo", true);
+    expect(await app.getHtml("pre")).toMatch(
+      JSON.stringify(["idle/undefined"])
+    );
+
+    await page.fill("#fetcher-input", "1");
+    await app.clickElement("#fetcher-load");
+    await page.waitForSelector("#fetcher-idle");
+    expect(await app.getHtml("pre")).toMatch(
+      JSON.stringify(["idle/undefined", "loading/undefined", "idle/LOADER 1"])
+    );
+
+    await page.fill("#fetcher-input", "2");
+    await app.clickElement("#fetcher-load");
+    await page.waitForSelector("#fetcher-idle");
+    expect(await app.getHtml("pre")).toMatch(
+      JSON.stringify([
+        "idle/undefined",
+        "loading/undefined",
+        "idle/LOADER 1",
+        "loading/LOADER 1", // Preserves old data during reload
+        "idle/LOADER 2",
+      ])
+    );
+  });
+
+  test("fetcher.submit persists data through resubmissions", async ({
+    page,
+  }) => {
+    let app = new PlaywrightFixture(appFixture, page);
+
+    await app.goto("/fetcher-echo", true);
+    expect(await app.getHtml("pre")).toMatch(
+      JSON.stringify(["idle/undefined"])
+    );
+
+    await page.fill("#fetcher-input", "1");
+    await app.clickElement("#fetcher-submit");
+    await page.waitForSelector("#fetcher-idle");
+    expect(await app.getHtml("pre")).toMatch(
+      JSON.stringify([
+        "idle/undefined",
+        "submitting/undefined",
+        "loading/ACTION 1",
+        "idle/ACTION 1",
+      ])
+    );
+
+    await page.fill("#fetcher-input", "2");
+    await app.clickElement("#fetcher-submit");
+    await page.waitForSelector("#fetcher-idle");
+    expect(await app.getHtml("pre")).toMatch(
+      JSON.stringify([
+        "idle/undefined",
+        "submitting/undefined",
+        "loading/ACTION 1",
+        "idle/ACTION 1",
+        "submitting/ACTION 1", // Preserves old data during resubmissions
+        "loading/ACTION 2",
+        "idle/ACTION 2",
+      ])
+    );
+  });
 });

packages/remix-react/components.tsx

@@ -1202,7 +1202,7 @@ function convertRouterFetcherToRemixFetcher(
           formData: formData,
           key: "",
         },
-        data: undefined,
+        data,
       };
       return fetcher;
     } else {
@@ -1285,7 +1285,7 @@ function convertRouterFetcherToRemixFetcher(
             formData: formData,
             key: "",
           },
-          data: undefined,
+          data,
         };
         return fetcher;
       }
@@ -1297,7 +1297,7 @@ function convertRouterFetcherToRemixFetcher(
     state: "loading",
     type: "normalLoad",
     submission: undefined,
-    data: undefined,
+    data,
   };
   return fetcher;
 }

packages/remix-react/transition.ts

@@ -120,7 +120,7 @@ export type FetcherStates<TData = any> = {
     formData: FormData;
     formEncType: string;
     submission: ActionSubmission;
-    data: undefined;
+    data: TData | undefined;
   };
   SubmittingLoader: {
     state: "submitting";