Do not attempt to deserialize empty json responses

.changeset/unlucky-planets-repeat.md

@@ -0,0 +1,5 @@
+---
+"@remix-run/router": patch
+---
+
+Do not attempt to deserialize empty JSON responses

packages/router/__tests__/navigation-test.ts

@@ -114,6 +114,24 @@ describe("navigations", () => {
       });
     });
 
+    // See: https://github.com/remix-run/react-router/issues/11145
+    it("does not attempt to deserialize empty json responses", async () => {
+      let t = initializeTest();
+      let A = await t.navigate("/foo");
+      await A.loaders.foo.resolve(
+        new Response(null, {
+          headers: {
+            "Content-Type": "application/json",
+          },
+        })
+      );
+      expect(t.router.state.errors).toBeNull();
+      expect(t.router.state.loaderData).toMatchObject({
+        root: "ROOT",
+        foo: null,
+      });
+    });
+
     it("unwraps non-redirect text Responses", async () => {
       let t = initializeTest();
       let A = await t.navigate("/foo");

packages/router/router.ts

@@ -4098,7 +4098,11 @@ async function callLoaderOrAction(
       // Check between word boundaries instead of startsWith() due to the last
       // paragraph of https://httpwg.org/specs/rfc9110.html#field.content-type
       if (contentType && /\bapplication\/json\b/.test(contentType)) {
-        data = await result.json();
+        if (result.body == null) {
+          data = null;
+        } else {
+          data = await result.json();
+        }
       } else {
         data = await result.text();
       }