From 58e47e8a3c8c1c1020bb210e3b0d78a9c35cf4ea Mon Sep 17 00:00:00 2001
From: Michael Dawson <michael_dawson@ca.ibm.com>
Date: Thu, 2 Nov 2017 18:14:24 -0400
Subject: [PATCH 1/3] doc: document common pattern for instanceof checks

Fixes: https://github.com/nodejs/node/issues/13824
---
 doc/api/n-api.md | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/doc/api/n-api.md b/doc/api/n-api.md
index 7bd20c60b60ea1..7ce19efbb3f021 100644
--- a/doc/api/n-api.md
+++ b/doc/api/n-api.md
@@ -3021,6 +3021,29 @@ constructor and methods can be called from JavaScript.
     callback, [`napi_unwrap`][] obtains the C++ instance that is the target of
     the call.
 
+For wrapped objects it may be difficult to distinguish between a function
+called on a class prototype and a function called on an instance of a class.
+A common pattern used to address this problem is to save a persistent
+reference to the class constructor for later `instanceof` checks.
+
+As an example:
+
+```
+napi_value MyClass_constructor = nullptr;
+status = napi_get_reference_value(env, MyClass::es_constructor, &MyClass_constructor);
+assert(napi_ok == status);
+bool is_instance = false;
+status = napi_instanceof(env, es_this, MyClass_constructor, &is_instance);
+assert(napi_ok == status);
+if (is_instance) {
+    // napi_unwrap() ...
+} else {
+    // otherwise...
+}
+```
+
+Of course you also need to make sure to free the reference once it is no longer needed.
+
 ### *napi_define_class*
 <!-- YAML
 added: v8.0.0

From dc5fee6fd7538cca96e72643c3e2c157d306ce9c Mon Sep 17 00:00:00 2001
From: Michael Dawson <michael_dawson@ca.ibm.com>
Date: Thu, 2 Nov 2017 18:17:47 -0400
Subject: [PATCH 2/3] squash: minor fixup

---
 doc/api/n-api.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/doc/api/n-api.md b/doc/api/n-api.md
index 7ce19efbb3f021..709466929b4d05 100644
--- a/doc/api/n-api.md
+++ b/doc/api/n-api.md
@@ -3028,7 +3028,7 @@ reference to the class constructor for later `instanceof` checks.
 
 As an example:
 
-```
+```C
 napi_value MyClass_constructor = nullptr;
 status = napi_get_reference_value(env, MyClass::es_constructor, &MyClass_constructor);
 assert(napi_ok == status);
@@ -3042,7 +3042,7 @@ if (is_instance) {
 }
 ```
 
-Of course you also need to make sure to free the reference once it is no longer needed.
+Of course the reference must be freed once it is no longer needed.
 
 ### *napi_define_class*
 <!-- YAML

From 192596f1e77ce8ab8f93af2227d4a32554dd4c0b Mon Sep 17 00:00:00 2001
From: Michael Dawson <michael_dawson@ca.ibm.com>
Date: Fri, 17 Nov 2017 09:02:52 -0500
Subject: [PATCH 3/3] squash: address comments

---
 doc/api/n-api.md | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/doc/api/n-api.md b/doc/api/n-api.md
index 709466929b4d05..7f8a415411adec 100644
--- a/doc/api/n-api.md
+++ b/doc/api/n-api.md
@@ -3036,13 +3036,13 @@ bool is_instance = false;
 status = napi_instanceof(env, es_this, MyClass_constructor, &is_instance);
 assert(napi_ok == status);
 if (is_instance) {
-    // napi_unwrap() ...
+  // napi_unwrap() ...
 } else {
-    // otherwise...
+  // otherwise...
 }
 ```
 
-Of course the reference must be freed once it is no longer needed.
+The reference must be freed once it is no longer needed.
 
 ### *napi_define_class*
 <!-- YAML