Fix for Electron v21 and up.

binding.gyp

@@ -5,6 +5,7 @@
     'zmq_no_sync_resolve%': 'false',
     'sanitizers%': 'false',
     'openssl_fips': '',
+    'runtime%': 'node',
   },
 
   'targets': [
@@ -51,7 +52,6 @@
       ],
 
       'defines': [
-        'NAPI_VERSION=3',
         'ZMQ_STATIC',
       ],
 
@@ -96,6 +96,9 @@
             }],
           ],
         }],
+        ['runtime=="electron"', {
+          "defines": ["NODE_RUNTIME_ELECTRON=1"]
+        }],
       ],
 
       'configurations': {

src/incoming_msg.cc

@@ -14,6 +14,7 @@ IncomingMsg::~IncomingMsg() {
 }
 
 Napi::Value IncomingMsg::IntoBuffer(const Napi::Env& env) {
+#if !(NODE_RUNTIME_ELECTRON && NODE_MODULE_VERSION >= 109) // 109 is Electron v21 and up
     if (moved) {
         /* If ownership has been transferred, do not attempt to read the buffer
            again in any case. This should not happen of course. */
@@ -22,10 +23,12 @@ Napi::Value IncomingMsg::IntoBuffer(const Napi::Env& env) {
     }
 
     static auto constexpr zero_copy_threshold = 1 << 7;
+#endif
 
     auto data = reinterpret_cast<uint8_t*>(zmq_msg_data(*ref));
     auto length = zmq_msg_size(*ref);
 
+#if !(NODE_RUNTIME_ELECTRON && NODE_MODULE_VERSION >= 109) // 109 is Electron v21 and up
     if (length > zero_copy_threshold) {
         /* Reuse existing buffer for external storage. This avoids copying but
            does include an overhead in having to call a finalizer when the
@@ -43,6 +46,7 @@ Napi::Value IncomingMsg::IntoBuffer(const Napi::Env& env) {
 
         return Napi::Buffer<uint8_t>::New(env, data, length, release, ref);
     }
+#endif
 
     if (length > 0) {
         return Napi::Buffer<uint8_t>::Copy(env, data, length);

src/prefix.h

@@ -2,6 +2,7 @@
 #pragma once
 
 #include <napi.h>
+#include <node_version.h>
 #define NAPI_BUILD_VERSION NAPI_VERSION
 
 #include <zmq.h>