From b6d56e1d98553eee02a07d69ba3c02f39cb9be2b Mon Sep 17 00:00:00 2001
From: Dominic Gannaway <dg@domgan.com>
Date: Mon, 16 Dec 2024 18:51:12 +0000
Subject: [PATCH] fix: remove unnecessary array state mutation warnings

---
 .changeset/lovely-geckos-visit.md             |  5 ++
 .../src/internal/client/dev/equality.js       | 70 -------------------
 .../src/internal/client/dom/operations.js     |  3 -
 3 files changed, 5 insertions(+), 73 deletions(-)
 create mode 100644 .changeset/lovely-geckos-visit.md

diff --git a/.changeset/lovely-geckos-visit.md b/.changeset/lovely-geckos-visit.md
new file mode 100644
index 000000000000..806db8eb6bc0
--- /dev/null
+++ b/.changeset/lovely-geckos-visit.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: remove unnecessary array state mutation warnings
diff --git a/packages/svelte/src/internal/client/dev/equality.js b/packages/svelte/src/internal/client/dev/equality.js
index 170f7baf95e9..a05210a9e5d9 100644
--- a/packages/svelte/src/internal/client/dev/equality.js
+++ b/packages/svelte/src/internal/client/dev/equality.js
@@ -1,76 +1,6 @@
 import * as w from '../warnings.js';
 import { get_proxied_value } from '../proxy.js';
 
-export function init_array_prototype_warnings() {
-	const array_prototype = Array.prototype;
-	// The REPL ends up here over and over, and this prevents it from adding more and more patches
-	// of the same kind to the prototype, which would slow down everything over time.
-	// @ts-expect-error
-	const cleanup = Array.__svelte_cleanup;
-	if (cleanup) {
-		cleanup();
-	}
-
-	const { indexOf, lastIndexOf, includes } = array_prototype;
-
-	array_prototype.indexOf = function (item, from_index) {
-		const index = indexOf.call(this, item, from_index);
-
-		if (index === -1) {
-			const test = indexOf.call(get_proxied_value(this), get_proxied_value(item), from_index);
-
-			if (test !== -1) {
-				w.state_proxy_equality_mismatch('array.indexOf(...)');
-			}
-		}
-
-		return index;
-	};
-
-	array_prototype.lastIndexOf = function (item, from_index) {
-		// we need to specify this.length - 1 because it's probably using something like
-		// `arguments` inside so passing undefined is different from not passing anything
-		const index = lastIndexOf.call(this, item, from_index ?? this.length - 1);
-
-		if (index === -1) {
-			// we need to specify this.length - 1 because it's probably using something like
-			// `arguments` inside so passing undefined is different from not passing anything
-			const test = lastIndexOf.call(
-				get_proxied_value(this),
-				get_proxied_value(item),
-				from_index ?? this.length - 1
-			);
-
-			if (test !== -1) {
-				w.state_proxy_equality_mismatch('array.lastIndexOf(...)');
-			}
-		}
-
-		return index;
-	};
-
-	array_prototype.includes = function (item, from_index) {
-		const has = includes.call(this, item, from_index);
-
-		if (!has) {
-			const test = includes.call(get_proxied_value(this), get_proxied_value(item), from_index);
-
-			if (test) {
-				w.state_proxy_equality_mismatch('array.includes(...)');
-			}
-		}
-
-		return has;
-	};
-
-	// @ts-expect-error
-	Array.__svelte_cleanup = () => {
-		array_prototype.indexOf = indexOf;
-		array_prototype.lastIndexOf = lastIndexOf;
-		array_prototype.includes = includes;
-	};
-}
-
 /**
  * @param {any} a
  * @param {any} b
diff --git a/packages/svelte/src/internal/client/dom/operations.js b/packages/svelte/src/internal/client/dom/operations.js
index 627bf917eee1..771dacaf2c33 100644
--- a/packages/svelte/src/internal/client/dom/operations.js
+++ b/packages/svelte/src/internal/client/dom/operations.js
@@ -1,7 +1,6 @@
 /** @import { TemplateNode } from '#client' */
 import { hydrate_node, hydrating, set_hydrate_node } from './hydration.js';
 import { DEV } from 'esm-env';
-import { init_array_prototype_warnings } from '../dev/equality.js';
 import { get_descriptor } from '../../shared/utils.js';
 
 // export these for reference in the compiled code, making global name deduplication unnecessary
@@ -54,8 +53,6 @@ export function init_operations() {
 	if (DEV) {
 		// @ts-expect-error
 		element_prototype.__svelte_meta = null;
-
-		init_array_prototype_warnings();
 	}
 }