update comments

packages/runner/injection/patches/cookies.ts

@@ -45,16 +45,7 @@ const sendCookieToServer = (cookie: AutomationCookie) => {
 // document.cookie runs into cross-origin restrictions when the AUT is on
 // a different origin than top. The goal is to make it act like it would
 // if the user's app was run in top.
-//
-// The general strategy is:
-// - Keep the document.cookie value (`documentCookieValue`) available so
-// the document.cookie getter can synchronously return it.
-// - Optimistically update that value when document.cookie is set, so that
-// subsequent synchronous calls to get the value will work.
-// - On an interval, get the browser's cookies for the given domain, so that
-// updates to the cookie jar (via http requests, cy.setCookie, etc) are
-// reflected in the document.cookie value.
-export const patchDocumentCookie = (originalCookies: AutomationCookie[]) => {
+export const patchDocumentCookie = (requestCookies: AutomationCookie[]) => {
  const url = location.href
  const domain = location.hostname
  const cookieJar = new CookieJar()
@@ -72,7 +63,10 @@ export const patchDocumentCookie = (originalCookies: AutomationCookie[]) => {
  })
  }
 
- addCookies(existingCookies.concat(originalCookies))
+ // requestCookies are ones included with the page request that's now being
+ // injected into. they're captured by the proxy and included statically in
+ // the injection so they can be added here and available before page load
+ addCookies(existingCookies.concat(requestCookies))
 
  Object.defineProperty(window.document, 'cookie', {
  get () {
@@ -116,6 +110,8 @@ export const patchDocumentCookie = (originalCookies: AutomationCookie[]) => {
 
  Cypress.on('test:before:run', reset)
 
+ // the following listeners are called from Cypress cookie commands, so that
+ // the document.cookie value is updated optimistically
  Cypress.on('set:cookie', (cookie: AutomationCookie) => {
  cookieJar.setCookie(automationCookieToToughCookie(cookie, domain), url, undefined)
  })