Make all params available to nested routes + parents (#7963)

* feat: Make all params available to nested routes (#7960)

* add test case

* update type imports

* bump file size limits

Co-authored-by: Michael Jackson <michael@jackson.us>

package.json

@@ -76,13 +76,13 @@
       "none": "6 kB"
     },
     "build/react-router/umd/react-router.production.min.js": {
-      "none": "7 kB"
+      "none": "8 kB"
     },
     "build/react-router-dom/react-router-dom.production.min.js": {
       "none": "3 kB"
     },
     "build/react-router-dom/umd/react-router-dom.production.min.js": {
-      "none": "7 kB"
+      "none": "8 kB"
     }
   },
   "prettier": {

packages/react-router/__tests__/useParams-test.tsx

@@ -193,4 +193,33 @@ describe("useParams", () => {
       );
     });
   });
+
+  describe("when the params match in a child route", () => {
+    it("renders params in the parent", () => {
+      let params: Record<string, string> = {};
+      function Blog() {
+        params = useParams();
+        return <h1>{params.slug}</h1>;
+      }
+
+      function BlogPost() {
+        return null;
+      }
+
+      createTestRenderer(
+        <Router initialEntries={["/blog/react-router"]}>
+          <Routes>
+            <Route path="/blog" element={<Blog />}>
+              <Route path=":slug" element={<BlogPost />} />
+            </Route>
+          </Routes>
+        </Router>
+      );
+
+      expect(typeof params).toBe("object");
+      expect(params).toMatchObject({
+        slug: "react-router"
+      });
+    });
+  });
 });

packages/react-router/index.tsx

@@ -1,6 +1,6 @@
 import * as React from "react";
-import {
-  Action,
+import { Action, createMemoryHistory, parsePath } from "history";
+import type {
   Blocker,
   History,
   InitialEntry,
@@ -10,9 +10,7 @@ import {
   Path,
   State,
   To,
-  Transition,
-  createMemoryHistory,
-  parsePath
+  Transition
 } from "history";
 
 const readOnly: <T>(obj: T) => Readonly<T> = __DEV__
@@ -553,13 +551,15 @@ function useRoutes_(
   }
 
   // Otherwise render an element.
+  let allParams: Params = {};
   let element = matches.reduceRight((outlet, { params, pathname, route }) => {
+    allParams = { ...allParams, ...params };
     return (
       <RouteContext.Provider
         children={route.element}
         value={{
           outlet,
-          params: readOnly<Params>({ ...parentParams, ...params }),
+          params: readOnly<Params>({ ...parentParams, ...allParams }),
           pathname: joinPaths([basenameForMatching, pathname]),
           basename,
           route