From d59f41fb5d0c00ea0fbf970d53f5cf4fbf1b82cf Mon Sep 17 00:00:00 2001
From: James M Snell <jasnell@gmail.com>
Date: Fri, 29 Nov 2024 08:24:11 -0800
Subject: [PATCH] net: add net.BlockList.isBlockList(value)

---
 doc/api/net.md                  | 9 +++++++++
 lib/internal/blocklist.js       | 9 +++++++++
 test/parallel/test-blocklist.js | 5 +++++
 3 files changed, 23 insertions(+)

diff --git a/doc/api/net.md b/doc/api/net.md
index 513c405d80e66d..770398a7ef2bb5 100644
--- a/doc/api/net.md
+++ b/doc/api/net.md
@@ -170,6 +170,15 @@ added:
 
 The list of rules added to the blocklist.
 
+### `BlockList.isBlockList(value)`
+
+<!-- YAML
+added: REPLACEME
+-->
+
+* `value` {any} Any JS value
+* Returns `true` if the `value` is a `net.BlockList`.
+
 ## Class: `net.SocketAddress`
 
 <!-- YAML
diff --git a/lib/internal/blocklist.js b/lib/internal/blocklist.js
index d4eb35c9a70cb8..a992a6b8f0703c 100644
--- a/lib/internal/blocklist.js
+++ b/lib/internal/blocklist.js
@@ -43,6 +43,15 @@ class BlockList {
     this[kHandle][owner_symbol] = this;
   }
 
+  /**
+   * Returns true if the value is a BlockList
+   * @param {any} value
+   * @returns {boolean}
+   */
+  static isBlockList(value) {
+    return value?.[kHandle] !== undefined;
+  }
+
   [kInspect](depth, options) {
     if (depth < 0)
       return this;
diff --git a/test/parallel/test-blocklist.js b/test/parallel/test-blocklist.js
index ddd9a4e4957279..4b1bc78cd5ac92 100644
--- a/test/parallel/test-blocklist.js
+++ b/test/parallel/test-blocklist.js
@@ -282,3 +282,8 @@ const util = require('util');
   assert(!blocklist.check('1.1.1.2'));
   assert(!blocklist.check('2.3.4.5'));
 }
+
+{
+  assert(BlockList.isBlockList(new BlockList()));
+  assert(!BlockList.isBlockList({}));
+}