Add some hooks for React 16.8 users

- useMatch
- useParams
- useLocation
- useHistory

Author: mjackson

Diff for: packages/react-router-dom/.size-snapshot.json

@@ -1,26 +1,26 @@
 {
   "esm/react-router-dom.js": {
-    "bundled": 8797,
-    "minified": 5223,
-    "gzipped": 1682,
+    "bundled": 9444,
+    "minified": 5645,
+    "gzipped": 1786,
     "treeshaked": {
       "rollup": {
-        "code": 379,
-        "import_statements": 355
+        "code": 2272,
+        "import_statements": 432
       },
       "webpack": {
-        "code": 1612
+        "code": 3572
       }
     }
   },
   "umd/react-router-dom.js": {
-    "bundled": 129625,
-    "minified": 46107,
-    "gzipped": 14073
+    "bundled": 131334,
+    "minified": 46991,
+    "gzipped": 14275
   },
   "umd/react-router-dom.min.js": {
-    "bundled": 86293,
-    "minified": 29465,
-    "gzipped": 9792
+    "bundled": 87085,
+    "minified": 29827,
+    "gzipped": 9885
   }
 }

Diff for: packages/react-router/.size-snapshot.json

@@ -1,26 +1,26 @@
 {
   "esm/react-router.js": {
-    "bundled": 23515,
-    "minified": 13336,
-    "gzipped": 3696,
+    "bundled": 24890,
+    "minified": 14513,
+    "gzipped": 3839,
     "treeshaked": {
       "rollup": {
-        "code": 2376,
+        "code": 2389,
         "import_statements": 470
       },
       "webpack": {
-        "code": 3743
+        "code": 3758
       }
     }
   },
   "umd/react-router.js": {
-    "bundled": 102011,
-    "minified": 36085,
-    "gzipped": 11534
+    "bundled": 103056,
+    "minified": 36690,
+    "gzipped": 11666
   },
   "umd/react-router.min.js": {
-    "bundled": 62277,
-    "minified": 21931,
-    "gzipped": 7707
+    "bundled": 62526,
+    "minified": 22088,
+    "gzipped": 7748
   }
 }

Diff for: packages/react-router/modules/__tests__/useHistory-test.js

@@ -0,0 +1,34 @@
+import React from "react";
+import ReactDOM from "react-dom";
+import { MemoryRouter, Route, useHistory } from "react-router";
+
+import renderStrict from "./utils/renderStrict.js";
+
+describe("useHistory", () => {
+  const node = document.createElement("div");
+
+  afterEach(() => {
+    ReactDOM.unmountComponentAtNode(node);
+  });
+
+  it("returns the history object", () => {
+    let history;
+
+    function HomePage() {
+      history = useHistory();
+      return null;
+    }
+
+    renderStrict(
+      <MemoryRouter initialEntries={["/home"]}>
+        <Route path="/home">
+          <HomePage />
+        </Route>
+      </MemoryRouter>,
+      node
+    );
+
+    expect(typeof history).toBe("object");
+    expect(typeof history.push).toBe("function");
+  });
+});

Diff for: packages/react-router/modules/__tests__/useLocation-test.js

@@ -0,0 +1,36 @@
+import React from "react";
+import ReactDOM from "react-dom";
+import { MemoryRouter, Route, useLocation } from "react-router";
+
+import renderStrict from "./utils/renderStrict.js";
+
+describe("useLocation", () => {
+  const node = document.createElement("div");
+
+  afterEach(() => {
+    ReactDOM.unmountComponentAtNode(node);
+  });
+
+  it("returns the current location object", () => {
+    let location;
+
+    function HomePage() {
+      location = useLocation();
+      return null;
+    }
+
+    renderStrict(
+      <MemoryRouter initialEntries={["/home"]}>
+        <Route path="/home">
+          <HomePage />
+        </Route>
+      </MemoryRouter>,
+      node
+    );
+
+    expect(typeof location).toBe("object");
+    expect(location).toMatchObject({
+      pathname: "/home"
+    });
+  });
+});

Diff for: packages/react-router/modules/__tests__/useMatch-test.js

@@ -0,0 +1,38 @@
+import React from "react";
+import ReactDOM from "react-dom";
+import { MemoryRouter, Route, useMatch } from "react-router";
+
+import renderStrict from "./utils/renderStrict.js";
+
+describe("useMatch", () => {
+  const node = document.createElement("div");
+
+  afterEach(() => {
+    ReactDOM.unmountComponentAtNode(node);
+  });
+
+  it("returns the match object", () => {
+    let match;
+
+    function HomePage() {
+      match = useMatch();
+      return null;
+    }
+
+    renderStrict(
+      <MemoryRouter initialEntries={["/home"]}>
+        <Route path="/home">
+          <HomePage />
+        </Route>
+      </MemoryRouter>,
+      node
+    );
+
+    expect(typeof match).toBe("object");
+    expect(match).toMatchObject({
+      path: "/home",
+      url: "/home",
+      isExact: true
+    });
+  });
+});

Diff for: packages/react-router/modules/__tests__/useParams-test.js

@@ -0,0 +1,101 @@
+import React from "react";
+import ReactDOM from "react-dom";
+import { MemoryRouter, Route, useMatch, useParams } from "react-router";
+
+import renderStrict from "./utils/renderStrict.js";
+
+describe("useParams", () => {
+  const node = document.createElement("div");
+
+  afterEach(() => {
+    ReactDOM.unmountComponentAtNode(node);
+  });
+
+  describe("when the path has no params", () => {
+    it("returns an empty hash", () => {
+      let params;
+
+      function HomePage() {
+        params = useParams();
+        return null;
+      }
+
+      renderStrict(
+        <MemoryRouter initialEntries={["/home"]}>
+          <Route path="/home">
+            <HomePage />
+          </Route>
+        </MemoryRouter>,
+        node
+      );
+
+      expect(typeof params).toBe("object");
+      expect(Object.keys(params)).toHaveLength(0);
+    });
+  });
+
+  describe("when the path has some params", () => {
+    it("returns a hash of the URL params and their values", () => {
+      let params;
+
+      function BlogPost() {
+        params = useParams();
+        return null;
+      }
+
+      renderStrict(
+        <MemoryRouter initialEntries={["/blog/cupcakes"]}>
+          <Route path="/blog/:slug">
+            <BlogPost />
+          </Route>
+        </MemoryRouter>,
+        node
+      );
+
+      expect(typeof params).toBe("object");
+      expect(params).toMatchObject({
+        slug: "cupcakes"
+      });
+    });
+
+    describe("a child route", () => {
+      it("returns a combined hash of the parent and child params", () => {
+        let params;
+
+        function Course() {
+          params = useParams();
+          return null;
+        }
+
+        function Users() {
+          const match = useMatch();
+          return (
+            <div>
+              <h1>Users</h1>
+              <Route path={`${match.path}/courses/:course`}>
+                <Course />
+              </Route>
+            </div>
+          );
+        }
+
+        renderStrict(
+          <MemoryRouter
+            initialEntries={["/users/mjackson/courses/react-router"]}
+          >
+            <Route path="/users/:username">
+              <Users />
+            </Route>
+          </MemoryRouter>,
+          node
+        );
+
+        expect(typeof params).toBe("object");
+        expect(params).toMatchObject({
+          username: "mjackson",
+          course: "react-router"
+        });
+      });
+    });
+  });
+});

Diff for: packages/react-router/modules/hooks.js

@@ -0,0 +1,50 @@
+import React from "react";
+import invariant from "tiny-invariant";
+
+import Context from "./RouterContext.js";
+
+const useContext = React.useContext;
+
+export function useMatch() {
+  if (__DEV__) {
+    invariant(
+      typeof useContext === "function",
+      "You must use React >= 16.8 in order to use useMatch()"
+    );
+  }
+
+  return useContext(Context).match;
+}
+
+export function useParams() {
+  if (__DEV__) {
+    invariant(
+      typeof useContext === "function",
+      "You must use React >= 16.8 in order to use useParams()"
+    );
+  }
+
+  return useMatch().params;
+}
+
+export function useLocation() {
+  if (__DEV__) {
+    invariant(
+      typeof useContext === "function",
+      "You must use React >= 16.8 in order to use useLocation()"
+    );
+  }
+
+  return useContext(Context).location;
+}
+
+export function useHistory() {
+  if (__DEV__) {
+    invariant(
+      typeof useContext === "function",
+      "You must use React >= 16.8 in order to use useHistory()"
+    );
+  }
+
+  return useContext(Context).history;
+}

Diff for: packages/react-router/modules/index.js

@@ -32,4 +32,7 @@ export { default as generatePath } from "./generatePath";
 export { default as matchPath } from "./matchPath";
 export { default as withRouter } from "./withRouter";
 
+import { useMatch, useParams, useLocation, useHistory } from "./hooks.js";
+export { useMatch, useParams, useLocation, useHistory };
+
 export { default as __RouterContext } from "./RouterContext";