Fix expiry time not updating when cookie is updated

lib/__tests__/cookieJar.spec.ts

@@ -498,7 +498,7 @@
           url,
         )
         jest.advanceTimersByTime(2000) // so that 'h=8' expires
       })
 
       it('should be able to get the cookies for http://nodejs.org', async () => {
         const cookies = await cookieJar.getCookies('http://nodejs.org')
@@ -1203,6 +1203,48 @@
   expect('/notauth' in pollutedObject).toBe(false)
 })
 
+it('should fix issue #154 - Expiry should not be affected by creation date', async () => {
+  // setting the time to zero here just to make it obvious that the expiry time is updated
+  jest.useFakeTimers({ now: 0 })
+
+  const jar = new CookieJar()
+
+  await jar.setCookie('foo=bar; Max-Age=60;', 'https://example.com')
+
+  const initialCookies = await jar.getCookies('https://example.com')
+  expect(initialCookies).toEqual([
+    expect.objectContaining({
+      key: 'foo',
+      value: 'bar',
+      path: '/',
+      domain: 'example.com',
+      maxAge: 60,
+    }),
+  ])
+  // the expiry time should be 60s from now (0)
+  expect(initialCookies[0]?.expiryTime()).toBe(60 * 1000)
+
+  // advance the time by 1s, so now = 1000
+  jest.advanceTimersByTime(1000)
+
+  await jar.setCookie('foo=bar; Max-Age=60;', 'https://example.com')
+
+  const updatedCookies = await jar.getCookies('https://example.com')
+  expect(updatedCookies).toEqual([
+    expect.objectContaining({
+      key: 'foo',
+      value: 'bar',
+      path: '/',
+      domain: 'example.com',
+      maxAge: 60,
+      // the creation time should be unchanged as per the spec
+      creation: initialCookies[0]?.creation,
+    }),
+  ])
+  // the expiry time should be 60s from now (1000)
+  expect(updatedCookies[0]?.expiryTime()).toBe(60 * 1000 + 1000)
+})
+
 // special use domains under a sub-domain
 describe.each(['local', 'example', 'invalid', 'localhost', 'test'])(
   'when special use domain is dev.%s',

lib/cookie/cookie.ts

@@ -671,7 +671,7 @@ export class Cookie {
   // elsewhere)
   expiryTime(now?: Date): number | undefined {
     if (this.maxAge != null) {
-      const relativeTo = now || this.creation || new Date()
+      const relativeTo = now || this.lastAccessed || new Date()
       const maxAge = typeof this.maxAge === 'number' ? this.maxAge : -Infinity
       const age = maxAge <= 0 ? -Infinity : maxAge * 1000
       if (relativeTo === 'Infinity') {