Fix additional entry inejcted to params (#124)

* fix additional entry inejcted to params ..

* add unit test for this case ..

lib/layer.js

@@ -24,9 +24,9 @@ function Layer(path, methods, middleware, opts) {
   this.paramNames = [];
   this.stack = Array.isArray(middleware) ? middleware : [middleware];
 
-  for(let i = 0; i < methods.length; i++) {
+  for (let i = 0; i < methods.length; i++) {
     const l = this.methods.push(methods[i].toUpperCase());
-    if (this.methods[l-1] === 'GET') this.methods.unshift('HEAD');
+    if (this.methods[l - 1] === 'GET') this.methods.unshift('HEAD');
   }
 
   // ensure middleware is a function
@@ -68,10 +68,10 @@ Layer.prototype.match = function (path) {
 Layer.prototype.params = function (path, captures, existingParams) {
   const params = existingParams || {};
 
-  for (let len = captures.length, i=0; i<len; i++) {
+  for (let len = captures.length, i = 0; i < len; i++) {
     if (this.paramNames[i]) {
       const c = captures[i];
-      params[this.paramNames[i].name] = c ? safeDecodeURIComponent(c) : c;
+      if (c && c.length !== 0) params[this.paramNames[i].name] = c ? safeDecodeURIComponent(c) : c;
     }
   }
 
@@ -125,7 +125,7 @@ Layer.prototype.url = function (params, options) {
   let replace = {};
 
   if (args instanceof Array) {
-    for (let len = tokens.length, i=0, j=0; i<len; i++) {
+    for (let len = tokens.length, i = 0, j = 0; i < len; i++) {
       if (tokens[i].name) replace[tokens[i].name] = args[j++];
     }
   } else if (tokens.some(token => token.name)) {