fix: preserve zero cookie values

index.js

@@ -159,7 +159,9 @@ function Cookie(name, value, attrs) {
   }
 
   this.name = name
-  this.value = value || ""
+  this.value = value || value === 0
+    ? String(value)
+    : ""
 
   for (var name in attrs) {
     this[name] = attrs[name]

test/cookie.js

@@ -8,6 +8,11 @@ describe('new Cookie(name, value, [options])', function () {
     assert.equal(cookie.constructor, cookies.Cookie)
   })
 
+  it('should preserve zero value', function () {
+    var cookie = new cookies.Cookie('foo', 0)
+    assert.strictEqual(cookie.toHeader(), 'foo=0; path=/; httponly')
+  })
+
   it('should throw on invalid name', function () {
     assert.throws(function () {
       new cookies.Cookie('foo\n', 'bar')

test/test.js

@@ -200,6 +200,14 @@ describe('new Cookies(req, res, [options])', function () {
         .end(done)
     })
 
+    it('should set numeric zero value', function (done) {
+      request(createServer(setCookieHandler('foo', 0)))
+        .get('/')
+        .expect(200)
+        .expect(shouldSetCookieToValue('foo', '0'))
+        .end(done)
+    })
+
     describe('when value is falsy', function () {
       it('should delete cookie', function (done) {
         request(createServer(setCookieHandler('foo', null)))