From 8eed005db6d2e3209ab9626c1c91ef9613857e38 Mon Sep 17 00:00:00 2001
From: RumovZ <gp5glkw78@relay.firefox.com>
Date: Mon, 18 Oct 2021 09:11:00 +0200
Subject: [PATCH] Use `null` for unset cardId

---
 qt/aqt/browser/card_info.py  | 6 ++++--
 ts/card-info/CardInfo.svelte | 4 ++--
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/qt/aqt/browser/card_info.py b/qt/aqt/browser/card_info.py
index 08def5750..61bdd2274 100644
--- a/qt/aqt/browser/card_info.py
+++ b/qt/aqt/browser/card_info.py
@@ -3,6 +3,7 @@
 
 from __future__ import annotations
 
+import json
 from typing import Callable
 
 import aqt
@@ -69,8 +70,9 @@ class CardInfoDialog(QDialog):
         self.update_card(card_id)
 
     def update_card(self, card_id: CardId | None) -> None:
-        val = "undefined" if card_id is None else card_id
-        self.web.eval(f"cardInfo.then((c) => c.$set({{ cardId: {val} }}));")
+        self.web.eval(
+            f"cardInfo.then((c) => c.$set({{ cardId: {json.dumps(card_id)} }}));"
+        )
 
     def reject(self) -> None:
         if self._on_close:
diff --git a/ts/card-info/CardInfo.svelte b/ts/card-info/CardInfo.svelte
index 6dec99e15..5ec718efb 100644
--- a/ts/card-info/CardInfo.svelte
+++ b/ts/card-info/CardInfo.svelte
@@ -9,12 +9,12 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
     import CardStats from "./CardStats.svelte";
     import Revlog from "./Revlog.svelte";
 
-    export let cardId: number | undefined = undefined;
+    export let cardId: number | null = null;
     export let includeRevlog: boolean = true;
 
     let stats: Stats.CardStatsResponse | undefined;
 
-    $: if (cardId === undefined) {
+    $: if (cardId === null) {
         stats = undefined;
     } else {
         const sentCardId = cardId;