quic: proper custom inspect for QuicEndpoint

PR-URL: #34247
Reviewed-By: Anna Henningsen <anna@addaleax.net>

lib/internal/quic/core.js

@@ -24,6 +24,7 @@ const {
 const { Buffer } = require('buffer');
 const { isArrayBufferView } = require('internal/util/types');
 const {
+  customInspect,
   getAllowUnauthorized,
   getSocketType,
   lookup4,
@@ -638,14 +639,12 @@ class QuicEndpoint {
     socket[kHandle].addEndpoint(handle, preferred);
   }
 
-  [kInspect]() {
-    // TODO(@jasnell): Proper custom inspect implementation
-    const obj = {
+  [kInspect](depth, options) {
+    return customInspect(this, {
       address: this.address,
-      fd: this[kInternalState].fd,
+      fd: this.fd,
       type: this[kInternalState].type === AF_INET6 ? 'udp6' : 'udp4'
-    };
-    return `QuicEndpoint ${util.format(obj)}`;
+    }, depth, options);
   }
 
   // afterLookup is invoked when binding a QuicEndpoint. The first
@@ -741,7 +740,8 @@ class QuicEndpoint {
   }
 
   get fd() {
-    return this[kInternalState].fd;
+    return this[kInternalState].fd >= 0 ?
+      this[kInternalState].fd : undefined;
   }
 
   // True if the QuicEndpoint has been destroyed and is

lib/internal/quic/util.js

@@ -23,6 +23,8 @@ const {
   },
 } = require('internal/async_hooks');
 
+const { inspect } = require('internal/util/inspect');
+
 const { Readable } = require('stream');
 const {
   kHandle,
@@ -955,7 +957,20 @@ class QLogStream extends Readable {
   }
 }
 
+function customInspect(self, obj, depth, options) {
+  if (depth < 0)
+    return self;
+
+  const opts = {
+    ...options,
+    depth: options.depth == null ? null : options.depth - 1
+  };
+
+  return `${self.constructor.name} ${inspect(obj, opts)}`;
+}
+
 module.exports = {
+  customInspect,
   getAllowUnauthorized,
   getSocketType,
   lookup4,