From b5eb61d5419aee5f439457e53bd0f89a02d2842a Mon Sep 17 00:00:00 2001
From: Claude <noreply@anthropic.com>
Date: Sun, 7 Jun 2026 20:51:58 +0000
Subject: [PATCH] fix: three bugs from second code review

- state.js: wrap JSON.parse in try/catch in loadLocalPlayers/loadLocalMatches;
  corrupt localStorage no longer crashes the app or blocks the remote fetch
- chart.js: destroy chartInstance before early-returning on empty data in
  renderEloChart to avoid Chart.js "canvas already in use" on next render
- app.js: remove dead `match` variable in removeMatch (leftover from the
  targeted-write optimisation that was reverted in PR #25)

https://claude.ai/code/session_01TgxiTLy7fCh5xZPJT8eTVt
---
 app.js       |  1 -
 src/chart.js |  4 ++++
 src/state.js | 20 ++++++++++++++++----
 3 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/app.js b/app.js
index c5d8016..1cfc8ca 100644
--- a/app.js
+++ b/app.js
@@ -341,7 +341,6 @@ async function removeMatch(id) {
     toggleLoading(true);
 
     try {
-        const match = state.matches.find(m => m.id === id);
         await deleteMatch(id);
 
         state.matches = state.matches.filter(m => m.id !== id);
diff --git a/src/chart.js b/src/chart.js
index ca2b539..14b5359 100644
--- a/src/chart.js
+++ b/src/chart.js
@@ -184,6 +184,10 @@ export function renderEloChart(type = 'singles') {
         .sort((a, b) => a[1].name.localeCompare(b[1].name));
 
     if (activePlayers.length === 0) {
+        if (chartInstance) {
+            chartInstance.destroy();
+            chartInstance = null;
+        }
         let msg = canvas.parentElement.querySelector('.chart-empty-msg');
         if (!msg) {
             msg = document.createElement('p');
diff --git a/src/state.js b/src/state.js
index 72d177d..147ab53 100644
--- a/src/state.js
+++ b/src/state.js
@@ -41,14 +41,26 @@ export function persistMatches() {
 
 export function loadLocalPlayers() {
     const raw = localStorage.getItem('eloPlayers');
-    if (raw) state.players = JSON.parse(raw);
-    return !!raw;
+    if (!raw) return false;
+    try {
+        state.players = JSON.parse(raw);
+        return true;
+    } catch {
+        localStorage.removeItem('eloPlayers');
+        return false;
+    }
 }
 
 export function loadLocalMatches() {
     const raw = localStorage.getItem('eloMatches');
-    if (raw) state.matches = JSON.parse(raw);
-    return !!raw;
+    if (!raw) return false;
+    try {
+        state.matches = JSON.parse(raw);
+        return true;
+    } catch {
+        localStorage.removeItem('eloMatches');
+        return false;
+    }
 }
 
 // ================= STATISTIK-NEUBERECHNUNG =================