refactor: Squeeze some more performance out of clearCookie

Plus various other refactoring.

cookie.js

@@ -1,10 +1,8 @@
 'use strict';
 
-const {parse: parseCookie, serialize: serializeCookie} = require('cookie');
+const {parse, serialize} = require('cookie');
 const {sign, unsign} = require('cookie-signature');
 
-const clearCookieExpiresDate = new Date(1);
-
 function cookie(app, {secret} = {}) {
   app.decorateRequest('cookies', null);
 
@@ -24,24 +22,33 @@ function cookie(app, {secret} = {}) {
 
 function onRequest(req, res, next) {
   const cookieHeader = req.headers.cookie;
-  req.cookies = cookieHeader === undefined ? {} : parseCookie(cookieHeader);
+
+  req.cookies = cookieHeader === undefined ? {} : parse(cookieHeader);
+
   next();
 }
 
 function setCookie(name, value, options) {
-  options = Object.assign({path: '/'}, options);
-  this.append('set-cookie', serializeCookie(name, value, options));
+  const opts = Object.assign({path: '/'}, options);
+
+  this.append('set-cookie', serialize(name, value, opts));
 
   return this;
 }
 
+const clearCookieExpiresDate = new Date(1);
+
 function clearCookie(name, options) {
   // IE/Edge don't support Max-Age=0, so use Expires instead
-  options = Object.assign({expires: null, maxAge: null}, options);
-  options.expires = clearCookieExpiresDate;
-  options.maxAge = null; // In case options contains maxAge
+  const clearOpts = Object.assign({
+    expires: clearCookieExpiresDate,
+    maxAge: null,
+    path: '/',
+  }, options);
+
+  clearOpts.maxAge = null; // In case options contains maxAge
 
-  this.setCookie(name, '', options);
+  this.append('set-cookie', serialize(name, '', clearOpts));
 
   return this;
 }

test/test.js

@@ -79,7 +79,7 @@ describe('res.clearCookie()', () => {
     const app = makeApp();
 
     app.get('/', (req, res) => {
-      res.clearCookie('foo', 'bar');
+      res.clearCookie('foo');
       res.send();
     });
 
@@ -90,18 +90,33 @@ describe('res.clearCookie()', () => {
     );
   });
 
+  it('should clear a cookie with options', async () => {
+    const app = makeApp();
+
+    app.get('/', (req, res) => {
+      res.clearCookie('foo', {maxAge: 3600, httpOnly: true, secure: true});
+      res.send();
+    });
+
+    const res = await app.request('/');
+    assert.deepStrictEqual(
+      res.headers['set-cookie'],
+      ['foo=; Path=/; Expires=Thu, 01 Jan 1970 00:00:00 GMT; HttpOnly; Secure']
+    );
+  });
+
   it('should clear multiple cookies', async () => {
     const app = makeApp();
 
     app.get('/', (req, res) => {
-      res.clearCookie('a', {expires: new Date()});
-      res.clearCookie('b', {maxAge: 3600, httpOnly: true, secure: true});
+      res.clearCookie('a', {path: '/some/path'});
+      res.clearCookie('b', {httpOnly: true, secure: true});
       res.send();
     });
 
     const res = await app.request('/');
     assert.deepStrictEqual(res.headers['set-cookie'], [
-      'a=; Path=/; Expires=Thu, 01 Jan 1970 00:00:00 GMT',
+      'a=; Path=/some/path; Expires=Thu, 01 Jan 1970 00:00:00 GMT',
       'b=; Path=/; Expires=Thu, 01 Jan 1970 00:00:00 GMT; HttpOnly; Secure',
     ]);
   });