Add .asRegExp() method to return regexp for route

README.md

@@ -27,6 +27,7 @@ Route = require('route-parser');
 var route = new Route('/my/fancy/route/page/:page');
 route.match('/my/fancy/route/page/7') // { page: 7 }
 route.reverse({page: 3}) // -> '/my/fancy/route/page/3'
+route.asRegExp() // new RegExp(/^\/my\/fancy\/route\/page\/([^/\?]+))?(?=\?|$)/)
 ```
 ## What can I use in my routes?
 

lib/route.js

@@ -68,5 +68,16 @@ Route.prototype.reverse = function (params) {
   return ReverseVisitor.visit(this.ast, params);
 };
 
+/**
+ * Returns a regular expression for matching the route
+ * @example
+ * var route = new Route('/route/:one/(:two)')
+ * route.asRegExp() // -> /\/route\/([^\\/\\?]+)\/(?:([^\\/\\?]+))?/
+ * @return {RegExp} The route expressed as a regular expression
+ */
+Route.prototype.asRegExp = function () {
+  var matcher = RegexpVisitor.visit(this.ast);
+  return matcher.re;
+};
 
 module.exports = Route;

test/test.js

@@ -171,4 +171,47 @@ describe('Route', function () {
       );
     });
   });
+
+  describe('asRegExp', function () {
+    it('returns regexp for route without params', function () {
+      var route = RouteParser('/foo');
+      var regexp = route.asRegExp();
+      assert.typeOf(regexp, 'regexp');
+      assert.match('/foo', regexp);
+      assert.match('/foo?', regexp);
+      assert.notMatch('/foo/', regexp);
+    });
+
+    it('returns regexp for route with simple params', function () {
+      var route = RouteParser('/:foo/:bar');
+      var regexp = route.asRegExp();
+      assert.typeOf(regexp, 'regexp');
+      assert.match('/red/green', regexp);
+    });
+
+    it('returns regexp for route with optional params', function () {
+      var route = RouteParser('/things/(option/:first)');
+      var regexp = route.asRegExp();
+      assert.typeOf(regexp, 'regexp');
+      assert.match('/things/', regexp);
+      assert.notMatch('/things/option/', regexp);
+      assert.match('/things/option/blue', regexp);
+    });
+
+    it('returns regexp for route with nested optional params', function () {
+      var route = RouteParser('/things/(option/:first(/second/:second))');
+      var regexp = route.asRegExp();
+      assert.typeOf(regexp, 'regexp');
+      assert.match('/things/', regexp);
+      assert.match('/things/option/blue', regexp);
+      assert.match('/things/option/blue/second/red', regexp);
+    });
+
+    it('returns regexp for route with splat', function () {
+      var route = RouteParser('/*a/foo/*b');
+      var regexp = route.asRegExp();
+      assert.typeOf(regexp, 'regexp');
+      assert.match('/zoo/woo/foo/bar/baz', regexp);
+    });
+  });
 });