docs: note about structured clone and DOM types (electron#26516)

nornagon · web-flow · commit 040ee66678af · 2020-11-17T11:11:40.000-08:00
diff --git a/docs/api/ipc-renderer.md b/docs/api/ipc-renderer.md
@@ -61,10 +61,15 @@ Algorithm][SCA], just like [`window.postMessage`][], so prototype chains will no
 included. Sending Functions, Promises, Symbols, WeakMaps, or WeakSets will
 throw an exception.
 
-> **NOTE**: Sending non-standard JavaScript types such as DOM objects or
+> **NOTE:** Sending non-standard JavaScript types such as DOM objects or
 > special Electron objects is deprecated, and will begin throwing an exception
 > starting with Electron 9.
 
+> **NOTE:** Since the main process does not have support for DOM objects such as
+> `ImageBitmap`, `File`, `DOMMatrix` and so on, such objects cannot be sent over
+> Electron's IPC to the main process, as the main process would have no way to decode
+> them. Attempting to send such objects over IPC will result in an error.
+
 The main process handles it by listening for `channel` with the
 [`ipcMain`](ipc-main.md) module.
 
@@ -89,6 +94,11 @@ throw an exception.
 > special Electron objects is deprecated, and will begin throwing an exception
 > starting with Electron 9.
 
+> **NOTE:** Since the main process does not have support for DOM objects such as
+> `ImageBitmap`, `File`, `DOMMatrix` and so on, such objects cannot be sent over
+> Electron's IPC to the main process, as the main process would have no way to decode
+> them. Attempting to send such objects over IPC will result in an error.
+
 The main process should listen for `channel` with
 [`ipcMain.handle()`](ipc-main.md#ipcmainhandlechannel-listener).
 
@@ -128,6 +138,11 @@ throw an exception.
 > special Electron objects is deprecated, and will begin throwing an exception
 > starting with Electron 9.
 
+> **NOTE:** Since the main process does not have support for DOM objects such as
+> `ImageBitmap`, `File`, `DOMMatrix` and so on, such objects cannot be sent over
+> Electron's IPC to the main process, as the main process would have no way to decode
+> them. Attempting to send such objects over IPC will result in an error.
+
 The main process handles it by listening for `channel` with [`ipcMain`](ipc-main.md) module,
 and replies by setting `event.returnValue`.
 
