util: improve performance inspecting proxies

This makes sure we do not retrieve the handler in case it's not
required. This improves the performance a tiny bit for these cases.

Backport-PR-URL: #31431
PR-URL: #30767
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Denys Otrishko <shishugi@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>

benchmark/util/inspect-proxy.js

@@ -4,7 +4,7 @@ const util = require('util');
 const common = require('../common.js');
 
 const bench = common.createBenchmark(main, {
-  n: [2e4],
+  n: [1e5],
   showProxy: [0, 1],
   isProxy: [0, 1]
 });

lib/internal/util/inspect.js

@@ -640,12 +640,12 @@ function formatValue(ctx, value, recurseTimes, typedArray) {
   const context = value;
   // Always check for proxies to prevent side effects and to prevent triggering
   // any proxy handlers.
-  const proxy = getProxyDetails(value);
+  const proxy = getProxyDetails(value, !!ctx.showProxy);
   if (proxy !== undefined) {
     if (ctx.showProxy) {
       return formatProxy(ctx, proxy, recurseTimes);
     }
-    value = proxy[0];
+    value = proxy;
   }
 
   // Provide a hook for user-specified inspect functions.

src/node_util.cc

@@ -91,15 +91,23 @@ static void GetProxyDetails(const FunctionCallbackInfo<Value>& args) {
   if (!args[0]->IsProxy())
     return;
 
+  CHECK(args[1]->IsBoolean());
+
   Local<Proxy> proxy = args[0].As<Proxy>();
 
-  Local<Value> ret[] = {
-    proxy->GetTarget(),
-    proxy->GetHandler()
-  };
+  if (args[1]->IsTrue()) {
+    Local<Value> ret[] = {
+      proxy->GetTarget(),
+      proxy->GetHandler()
+    };
 
-  args.GetReturnValue().Set(
-      Array::New(args.GetIsolate(), ret, arraysize(ret)));
+    args.GetReturnValue().Set(
+        Array::New(args.GetIsolate(), ret, arraysize(ret)));
+  } else {
+    Local<Value> ret = proxy->GetTarget();
+
+    args.GetReturnValue().Set(ret);
+  }
 }
 
 static void PreviewEntries(const FunctionCallbackInfo<Value>& args) {

test/parallel/test-util-inspect-proxy.js

@@ -43,10 +43,13 @@ util.inspect(proxyObj, opts);
 
 // getProxyDetails is an internal method, not intended for public use.
 // This is here to test that the internals are working correctly.
-const details = processUtil.getProxyDetails(proxyObj);
+let details = processUtil.getProxyDetails(proxyObj, true);
 assert.strictEqual(target, details[0]);
 assert.strictEqual(handler, details[1]);
 
+details = processUtil.getProxyDetails(proxyObj, false);
+assert.strictEqual(target, details);
+
 assert.strictEqual(
   util.inspect(proxyObj, opts),
   'Proxy [\n' +
@@ -105,7 +108,7 @@ const expected6 = 'Proxy [\n' +
                   '  ]\n' +
                   ']';
 assert.strictEqual(
-  util.inspect(proxy1, { showProxy: true, depth: null }),
+  util.inspect(proxy1, { showProxy: 1, depth: null }),
   expected1);
 assert.strictEqual(util.inspect(proxy2, opts), expected2);
 assert.strictEqual(util.inspect(proxy3, opts), expected3);