From 59fa5403732447c6d8a91920f716e123e9152b89 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Tue, 18 Apr 2023 15:54:45 +0200
Subject: [PATCH] use index instead

---
 src/runtime/internal/keyed_each.ts                    | 6 +++---
 test/runtime/samples/keyed-each-dev-unique/_config.js | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/runtime/internal/keyed_each.ts b/src/runtime/internal/keyed_each.ts
index 1e883832ba..8e1eced981 100644
--- a/src/runtime/internal/keyed_each.ts
+++ b/src/runtime/internal/keyed_each.ts
@@ -108,12 +108,12 @@ export function update_keyed_each(old_blocks, dirty, get_key, dynamic, ctx, list
 }
 
 export function validate_each_keys(ctx, list, get_context, get_key) {
-	const keys = new Set();
+	const keys = new Map();
 	for (let i = 0; i < list.length; i++) {
 		const key = get_key(get_context(ctx, list, i));
 		if (keys.has(key)) {
-			throw new Error(`Cannot have duplicate keys in a keyed each: ${key} is a duplicate`);
+			throw new Error(`Cannot have duplicate keys in a keyed each: Keys at index ${keys.get(key)} and ${i} are duplicates`);
 		}
-		keys.add(key);
+		keys.add(key, i);
 	}
 }
diff --git a/test/runtime/samples/keyed-each-dev-unique/_config.js b/test/runtime/samples/keyed-each-dev-unique/_config.js
index 8db814d43d..a932f2d1f6 100644
--- a/test/runtime/samples/keyed-each-dev-unique/_config.js
+++ b/test/runtime/samples/keyed-each-dev-unique/_config.js
@@ -3,5 +3,5 @@ export default {
 		dev: true
 	},
 
-	error: 'Cannot have duplicate keys in a keyed each: 1 is a duplicate'
+	error: 'Cannot have duplicate keys in a keyed each: Keys at index 0 and 3 are duplicates'
 };