From 8919ebf712347994ca0dd14640785f4a8473f105 Mon Sep 17 00:00:00 2001
From: Janek <janek.rahrt@me.com>
Date: Thu, 6 Jul 2023 13:42:40 +0200
Subject: [PATCH] fix: cross origin loading times

---
 src/adapter/window.ts   |  4 ++++
 src/link/popup.ts       | 28 ++++++++++++++++++++++------
 src/shared/constants.ts |  1 +
 src/types/index.ts      |  9 +++++----
 4 files changed, 32 insertions(+), 10 deletions(-)
 create mode 100644 src/shared/constants.ts

diff --git a/src/adapter/window.ts b/src/adapter/window.ts
index b74eda4..e24f552 100644
--- a/src/adapter/window.ts
+++ b/src/adapter/window.ts
@@ -1,6 +1,7 @@
 import { AnyProcedure, AnyRouter, TRPCError } from '@trpc/server';
 import { Unsubscribable, isObservable } from '@trpc/server/observable';
 
+import { TRPC_BROWSER_LOADED_EVENT } from '../shared/constants';
 import { isTRPCRequestWithId } from '../shared/trpcMessage';
 import type { MinimalWindow, TRPCChromeResponse } from '../types';
 import { CreateHandlerOptions } from './base';
@@ -22,6 +23,9 @@ export const createWindowHandler = <TRouter extends AnyRouter>(
     return;
   }
 
+  const loadListener = opts.postWindow ?? window.opener ?? window;
+  loadListener.postMessage(TRPC_BROWSER_LOADED_EVENT, { targetOrigin: postOrigin });
+
   // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment
   const { transformer } = router._def._config;
   const subscriptions = new Map<number | string, Unsubscribable>();
diff --git a/src/link/popup.ts b/src/link/popup.ts
index da90364..b3c5927 100644
--- a/src/link/popup.ts
+++ b/src/link/popup.ts
@@ -1,6 +1,7 @@
 import type { TRPCLink } from '@trpc/client';
 import type { AnyRouter } from '@trpc/server';
 
+import { TRPC_BROWSER_LOADED_EVENT } from '../shared/constants';
 import type { MinimalPopupWindow, MinimalWindow, TRPCChromeMessage } from '../types';
 import { createBaseLink } from './internal/base';
 
@@ -18,17 +19,32 @@ export const popupLink = <TRouter extends AnyRouter>(opts: PopupLinkOptions): TR
   const closeHandlerSet = new Set<() => void>();
 
   let popupWindow: MinimalPopupWindow | null = null;
-  async function getPopup() {
+  async function getPopup(loadListenWindow: MinimalWindow) {
     if (!popupWindow || popupWindow.closed) {
       popupWindow = opts.createPopup();
-      // wait til window is loaded
       await Promise.race([
+        // wait til window is loaded (same origin)
         new Promise((resolve) => {
-          popupWindow?.addEventListener?.('load', resolve);
+          try {
+            popupWindow?.addEventListener?.('load', resolve);
+          } catch {
+            // if this throws, it's a cross-origin popup and should stay pending (never resolve)
+          }
+        }),
+        // this is needed for cross-origin popups as they don't have a load event
+        new Promise<void>((resolve) => {
+          loadListenWindow.addEventListener('message', (event) => {
+            if (event.data === TRPC_BROWSER_LOADED_EVENT) {
+              resolve();
+            }
+          });
         }),
-        // expect the popup to load within 2.5s, this is needed for cross-origin popups as they don't have a load event
+        // expect the popup to load after 15s max, in case non of the above events fire
         new Promise((resolve) => {
-          setTimeout(resolve, 2500);
+          console.warn(
+            'Could not detect if popup loading succeeded after 15s timeout, continuing anyway',
+          );
+          setTimeout(resolve, 15000);
         }),
       ]);
 
@@ -59,7 +75,7 @@ export const popupLink = <TRouter extends AnyRouter>(opts: PopupLinkOptions): TR
 
   return createBaseLink({
     async postMessage(message) {
-      const popup = await getPopup();
+      const popup = await getPopup(opts.listenWindow);
       return popup.postMessage(message, {
         targetOrigin: opts.postOrigin,
       });
diff --git a/src/shared/constants.ts b/src/shared/constants.ts
new file mode 100644
index 0000000..2ef2dc2
--- /dev/null
+++ b/src/shared/constants.ts
@@ -0,0 +1 @@
+export const TRPC_BROWSER_LOADED_EVENT = 'TRPC_BROWSER::POPUP_LOADED';
diff --git a/src/types/index.ts b/src/types/index.ts
index bc9bbb7..4c2843d 100644
--- a/src/types/index.ts
+++ b/src/types/index.ts
@@ -10,6 +10,7 @@ export type TRPCChromeRequest = {
 };
 
 export type TRPCChromeSuccessResponse = {
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
   trpc: TRPCResultMessage<any>;
 };
 
@@ -22,10 +23,10 @@ export type TRPCChromeResponse = TRPCChromeSuccessResponse | TRPCChromeErrorResp
 export type TRPCChromeMessage = TRPCChromeRequest | TRPCChromeResponse;
 export type RelayedTRPCMessage = TRPCChromeMessage & { relayed?: true };
 
-export type MinimalWindow = Pick<
-  Window,
-  'postMessage' | 'addEventListener' | 'removeEventListener'
->;
+export interface MinimalWindow
+  extends Pick<Window, 'postMessage' | 'addEventListener' | 'removeEventListener'> {
+  opener?: MinimalWindow;
+}
 
 export type MinimalPopupWindow = Pick<Window, 'postMessage' | 'closed'> &
   // addEventListener/removeEventListener are only available on the same origin