PKG -- [fcl] Throw error on popup blocked, show error if sendMsgToFCL…

… parent reference doesn't exist (#1274)

.changeset/lovely-candles-relax.md

@@ -0,0 +1,5 @@
+---
+"@onflow/fcl": patch
+---
+
+Throw error if FCL popup is blocked. Show "session expired" if sendMsgToFCL cannot access parent window for postMessage.

packages/fcl/src/current-user/exec-service/strategies/utils/render-pop.js

@@ -6,11 +6,14 @@ let previousUrl = null
 function popupWindow(url, windowName, win, w, h) {
   const y = win.top.outerHeight / 2 + win.top.screenY - h / 2
   const x = win.top.outerWidth / 2 + win.top.screenX - w / 2
-  return win.open(
+  const popup = win.open(
     url,
     windowName,
     `toolbar=no, location=no, directories=no, status=no, menubar=no, scrollbars=no, resizable=no, copyhistory=no, width=${w}, height=${h}, top=${y}, left=${x}`
   )
+  if (!popup)
+    throw new Error("Popup failed to open (was it blocked by a popup blocker?)")
+  return popup
 }
 
 export function renderPop(src) {

packages/fcl/src/current-user/exec-service/strategies/utils/render-tab.js

@@ -6,6 +6,8 @@ let previousUrl = null
 export function renderTab(src) {
   if (tab == null || tab?.closed) {
     tab = window.open(src, "_blank")
+    if (!tab)
+      throw new Error("Tab failed to open (was it blocked by the browser?)")
   } else if (previousUrl !== src) {
     tab.location.replace(src)
     tab.focus()

packages/fcl/src/wallet-utils/send-msg-to-fcl.js

@@ -3,8 +3,10 @@ import {onMessageFromFCL} from "./on-message-from-fcl"
 export const sendMsgToFCL = (type, msg = {}) => {
   if (window.location !== window.parent.location) {
     window.parent.postMessage({...msg, type}, "*")
-  } else {
+  } else if (window.opener) {
     window.opener.postMessage({...msg, type}, "*")
+  } else {
+    throw new Error("Unable to communicate with parent FCL instance")
   }
 }