fix: depend on remendConfig content instead of its identity

package.json

@@ -71,6 +71,7 @@
     "@release-it/conventional-changelog": "^10.0.1",
     "@types/jest": "^29.5.14",
     "@types/react": "^19.1.12",
+    "@types/react-test-renderer": "^19.1.0",
     "commitlint": "^19.8.1",
     "del-cli": "^6.0.0",
     "eslint": "^9.35.0",
@@ -85,6 +86,7 @@
     "react-native-enriched-markdown": "0.6.0",
     "react-native-sse": "1.2.1",
     "react-native-worklets": "0.10.2",
+    "react-test-renderer": "19.2.3",
     "release-it": "^19.0.4",
     "remend": "1.3.0",
     "turbo": "^2.5.6",

src/__tests__/useStreamdownMarkdown.test.tsx

@@ -0,0 +1,55 @@
+import { act } from 'react';
+import TestRenderer from 'react-test-renderer';
+import { useStreamdownMarkdown } from '../hooks/useStreamdownMarkdown';
+
+jest.mock('../worklets/remendWorklet', () => ({
+  processRemendInWorklet: jest.fn(
+    (markdown: string, onComplete: (r: string) => void) => {
+      onComplete(markdown);
+    }
+  ),
+}));
+
+const { processRemendInWorklet } = jest.requireMock(
+  '../worklets/remendWorklet'
+) as {
+  processRemendInWorklet: jest.Mock;
+};
+
+function Consumer({ markdown, config }: { markdown: string; config: unknown }) {
+  useStreamdownMarkdown(markdown, { remendConfig: config as never });
+  return null;
+}
+
+describe('useStreamdownMarkdown', () => {
+  beforeEach(() => {
+    processRemendInWorklet.mockClear();
+  });
+
+  it('does not re-run the worklet job on idle re-renders when remendConfig is an inline literal', () => {
+    const Parent = ({ markdown }: { markdown: string }) => (
+      <Consumer markdown={markdown} config={{ katex: true }} />
+    );
+
+    let renderer!: TestRenderer.ReactTestRenderer;
+    act(() => {
+      renderer = TestRenderer.create(<Parent markdown="hi" />);
+    });
+    expect(processRemendInWorklet).toHaveBeenCalledTimes(1);
+
+    // Idle parent re-renders (same markdown) must not reschedule the job.
+    act(() => {
+      renderer.update(<Parent markdown="hi" />);
+    });
+    act(() => {
+      renderer.update(<Parent markdown="hi" />);
+    });
+    expect(processRemendInWorklet).toHaveBeenCalledTimes(1);
+
+    // A markdown change still schedules a new job.
+    act(() => {
+      renderer.update(<Parent markdown="hi there" />);
+    });
+    expect(processRemendInWorklet).toHaveBeenCalledTimes(2);
+  });
+});

src/hooks/useStreamdownMarkdown.ts

@@ -19,6 +19,11 @@ export function useStreamdownMarkdown(
   const [isStreaming, setIsStreaming] = useState(false);
   const versionRef = useRef(0);
 
+  // Gate the effect on the config's content, not its identity: an inline
+  // remendConfig is a fresh object every render and would otherwise reschedule
+  // the worklet job on every commit.
+  const remendConfigKey = JSON.stringify(options?.remendConfig);
+
   useEffect(() => {
     if (markdown === '') {
       setProcessedMarkdown('');
@@ -39,7 +44,9 @@ export function useStreamdownMarkdown(
       },
       options?.remendConfig
     );
-  }, [markdown, options?.remendConfig]);
+    // Reads the live options?.remendConfig; remendConfigKey gates re-runs.
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [markdown, remendConfigKey]);
 
   return { processedMarkdown, isStreaming };
 }

yarn.lock

@@ -3625,6 +3625,24 @@ __metadata:
   languageName: node
   linkType: hard
 
+"@types/react-test-renderer@npm:^19.1.0":
+  version: 19.1.0
+  resolution: "@types/react-test-renderer@npm:19.1.0"
+  dependencies:
+    "@types/react": "npm:*"
+  checksum: 10c0/799654e430df10aeaf267d71507fb64ec151359ead7e3774111bfd4abce7e0911dba461811195c06c22a6d17496ea92537d3185320ff4112fe29954cad1b9152
+  languageName: node
+  linkType: hard
+
+"@types/react@npm:*":
+  version: 19.2.18
+  resolution: "@types/react@npm:19.2.18"
+  dependencies:
+    csstype: "npm:^3.2.2"
+  checksum: 10c0/d04216172b4b4362b310017c210dfbe019fb4f4e7dffd0313e70b3acb3051d5c3e76e7e84e3cf4c6a3c824993ffadfe3949e589a6398a09d4200e7670e2962de
+  languageName: node
+  linkType: hard
+
 "@types/react@npm:^19.1.12, @types/react@npm:^19.2.0":
   version: 19.2.14
   resolution: "@types/react@npm:19.2.14"
@@ -10446,6 +10464,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"react-is@npm:^19.2.3":
+  version: 19.2.8
+  resolution: "react-is@npm:19.2.8"
+  checksum: 10c0/ed5322c84efe035c8fc814b1614ff5ca7fb8c2872a7c045197daf99f9b1bd68f32a2c79ffcbcfcff2fc5d93924ff9f9447400898f5b1534e6302bb0736a257f0
+  languageName: node
+  linkType: hard
+
 "react-native-builder-bob@npm:^0.40.18":
   version: 0.40.18
   resolution: "react-native-builder-bob@npm:0.40.18"
@@ -10564,6 +10589,7 @@ __metadata:
     "@release-it/conventional-changelog": "npm:^10.0.1"
     "@types/jest": "npm:^29.5.14"
     "@types/react": "npm:^19.1.12"
+    "@types/react-test-renderer": "npm:^19.1.0"
     commitlint: "npm:^19.8.1"
     del-cli: "npm:^6.0.0"
     eslint: "npm:^9.35.0"
@@ -10578,6 +10604,7 @@ __metadata:
     react-native-enriched-markdown: "npm:0.6.0"
     react-native-sse: "npm:1.2.1"
     react-native-worklets: "npm:0.10.2"
+    react-test-renderer: "npm:19.2.3"
     release-it: "npm:^19.0.4"
     remend: "npm:1.3.0"
     turbo: "npm:^2.5.6"
@@ -10674,6 +10701,18 @@ __metadata:
   languageName: node
   linkType: hard
 
+"react-test-renderer@npm:19.2.3":
+  version: 19.2.3
+  resolution: "react-test-renderer@npm:19.2.3"
+  dependencies:
+    react-is: "npm:^19.2.3"
+    scheduler: "npm:^0.27.0"
+  peerDependencies:
+    react: ^19.2.3
+  checksum: 10c0/842b82239dbddbc536083a6260c3e1b0507c02a3400bd05879fc19160468fd0f8ab79fec5dceffa6113b131835cc7621212f8415b46ea5156ab66bbfd7e24297
+  languageName: node
+  linkType: hard
+
 "react@npm:19.2.3":
   version: 19.2.3
   resolution: "react@npm:19.2.3"
@@ -11065,7 +11104,7 @@ __metadata:
   languageName: node
   linkType: hard
 
-"scheduler@npm:0.27.0":
+"scheduler@npm:0.27.0, scheduler@npm:^0.27.0":
   version: 0.27.0
   resolution: "scheduler@npm:0.27.0"
   checksum: 10c0/4f03048cb05a3c8fddc45813052251eca00688f413a3cee236d984a161da28db28ba71bd11e7a3dd02f7af84ab28d39fb311431d3b3772fed557945beb00c452