feat: add exclusive option

API.md

@@ -31,6 +31,7 @@ Create a new router.
 | --- | --- | --- |
 | [opts] | <code>Object</code> |  |
 | [opts.prefix] | <code>String</code> | prefix router paths |
+| [opts.exclusive] | <code>Boolean</code> | only run last matched route's controller when there are multiple matches |
 
 **Example**  
 Basic usage:

lib/router.js

@@ -43,6 +43,7 @@ module.exports = Router;
  *
  * @alias module:koa-router
  * @param {Object=} opts
+ * @param {Boolean=false} opts.exclusive only run last matched route's controller when there are multiple matches
  * @param {String=} opts.prefix prefix router paths
  * @constructor
  */
@@ -60,6 +61,7 @@ function Router(opts) {
     'POST',
     'DELETE'
   ];
+  this.exclusive = !!this.opts.exclusive;
 
   this.params = {};
   this.stack = [];
@@ -359,7 +361,7 @@ Router.prototype.routes = Router.prototype.middleware = function () {
       ctx._matchedRouteName = mostSpecificLayer.name;
     }
 
-    layerChain = matchedLayers.reduce(function(memo, layer) {
+    layerChain = (router.exclusive ? [mostSpecificLayer] : matchedLayers).reduce(function(memo, layer) {
       memo.push(function(ctx, next) {
         ctx.captures = layer.captures(path, ctx.captures);
         ctx.params = ctx.request.params = layer.params(path, ctx.captures, ctx.params);

test/lib/router.js

@@ -246,6 +246,56 @@ describe('Router', function () {
       })
   });
 
+  it('runs multiple controllers when there are multiple matches', function (done) {
+    const app = new Koa();
+    const router = new Router();
+
+    router
+      .get('users_single', '/users/:id(.*)', function (ctx, next) {
+        ctx.body = { single: true };
+        next();
+      })
+      .get('users_all', '/users/all', function (ctx, next) {
+        ctx.body = Object.assign({}, ctx.body, { all: true });
+        next();
+      });
+
+    request(http.createServer(app.use(router.routes()).callback()))
+      .get('/users/all')
+      .expect(200)
+      .end(function (err, res) {
+        if (err) return done(err);
+        expect(res.body).to.have.property('single', true);
+        expect(res.body).to.have.property('all', true);
+        done();
+      })
+  });
+
+  it('runs only the last match when the \'exclusive\' option is enabled', function (done) {
+    const app = new Koa();
+    const router = new Router({ exclusive: true });
+
+    router
+      .get('users_single', '/users/:id(.*)', function (ctx, next) {
+        ctx.body = { single: true };
+        next();
+      })
+      .get('users_all', '/users/all', function (ctx, next) {
+        ctx.body = Object.assign({}, ctx.body, { all: true });
+        next();
+      });
+
+    request(http.createServer(app.use(router.routes()).callback()))
+      .get('/users/all')
+      .expect(200)
+      .end(function (err, res) {
+        if (err) return done(err);
+        expect(res.body).to.not.have.property('single');
+        expect(res.body).to.have.property('all', true);
+        done();
+      })
+  });
+
   it('does not run subsequent middleware without calling next', function (done) {
     const app = new Koa();
     const router = new Router();