Parameter constraints

modules/components/Route.js

@@ -24,7 +24,7 @@ var RESERVED_PROPS = {
 /**
  * <Route> components specify components that are rendered to the page when the
  * URL matches a given pattern.
- * 
+ *
  * Routes are arranged in a nested tree structure. When a new URL is requested,
  * the tree is searched depth-first to find a route whose path matches the URL.
  * When one is found, all routes in the tree that lead to it are considered
@@ -251,7 +251,9 @@ function Redirect(to, params, query) {
 }
 
 function findMatches(path, route) {
-  var children = route.props.children, matches;
+  var children  = route.props.children,
+    constraints = route.props.constraints || {},
+    matches;
 
   // Check the subtree first to find the most deeply-nested match.
   if (Array.isArray(children)) {
@@ -276,7 +278,7 @@ function findMatches(path, route) {
   }
 
   // No routes in the subtree matched, so check this route.
-  var params = Path.extractParams(route.props.path, path);
+  var params = Path.extractParams(route.props.path, path, constraints);
 
   if (params)
     return [ makeMatch(route, params) ];

modules/helpers/Path.js

@@ -41,7 +41,7 @@ var Path = {
    * and returns an object of param name => value pairs. Returns null if the
    * pattern does not match the given path.
    */
-  extractParams: function (pattern, path) {
+  extractParams: function (pattern, path, constraints) {
     if (!isDynamicPattern(pattern)) {
       if (pattern === urlDecode(path))
         return {}; // No dynamic segments, but the paths match.
@@ -61,7 +61,29 @@ var Path = {
       params[paramName] = match[index + 1];
     });
 
-    return params;
+    if (this.testConstraints(params, constraints)) {
+      return params;
+    }
+
+    return null;
+  },
+
+  testConstraints: function (params, constraints) {
+    var pass = true;
+
+    if (! constraints) {
+      return true;
+    }
+
+    Object.keys(params).forEach(function(param) {
+      if (constraints[param]) {
+        if (! constraints[param].test(params[param])) {
+          pass = false;
+        }
+      }
+    });
+
+    return pass;
   },
 
   /**

specs/Path.spec.js

@@ -81,6 +81,23 @@ describe('Path.extractParams', function () {
       });
     });
   });
+
+  describe('when a pattern has dynamic segments with constraints', function() {
+    var pattern = '/comments/:id/edit',
+        constraints = {
+            id : /\d+/
+        };
+
+    describe('and the constraints match', function() {
+        expect(Path.extractParams(pattern, '/comments/123/edit', constraints))
+            .toEqual({ id : 123 });
+    });
+
+    describe('and the constraints do not match', function() {
+        expect(Path.extractParams(pattern, '/comments/abc/edit', constraints))
+            .toBe(null);
+    });
+  });
 });
 
 describe('Path.extractParamNames', function () {
@@ -118,7 +135,7 @@ describe('Path.injectParams', function () {
     describe('and a param is missing', function () {
       it('throws an Error', function () {
         expect(function () {
-          Path.injectParams(pattern, {})
+          Path.injectParams(pattern, {});
         }).toThrow(Error);
       });
     });
@@ -186,3 +203,33 @@ describe('Path.normalize', function () {
     });
   });
 });
+
+describe('Path.testConstraints', function () {
+  it('returns false when one or more constraints fail', function () {
+    var params = {
+      id   : 123,
+      name : 'Abc'
+    };
+
+    var constraints = {
+      id : /^\d+$/,
+      name : /^[a-z]+$/
+    };
+
+    expect(Path.testConstraints(params, constraints)).toBe(false);
+  });
+
+  it('returns true when constraints pass', function () {
+    var params = {
+      id   : 123,
+      name : 'Abc'
+    };
+
+    var constraints = {
+      id : /^\d+$/,
+      name : /^[A-Za-z]+$/
+    };
+
+    expect(Path.testConstraints(params, constraints)).toBe(true);
+  });
+});