util: add internal assignFunctionName() function

LiviaMedeiros · aduh95 · commit 6af5358f9c12 · 2025-06-10T11:34:07.000+02:00
PR-URL: #57916 Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com> Reviewed-By: Vinícius Lourenço Claro Cardoso <contact@viniciusl.com.br> Reviewed-By: James M Snell <jasnell@gmail.com>
diff --git a/lib/internal/util.js b/lib/internal/util.js
@@ -41,6 +41,7 @@ const {
   StringPrototypeToUpperCase,
   Symbol,
   SymbolFor,
+  SymbolPrototypeGetDescription,
   SymbolReplace,
   SymbolSplit,
 } = primordials;
@@ -67,6 +68,7 @@ const {
 } = internalBinding('util');
 const { isNativeError, isPromise } = internalBinding('types');
 const { getOptionValue } = require('internal/options');
+const assert = require('internal/assert');
 const { encodings } = internalBinding('string_decoder');
 
 const noCrypto = !process.versions.openssl;
@@ -897,10 +899,37 @@ const encodingsMap = { __proto__: null };
 for (let i = 0; i < encodings.length; ++i)
   encodingsMap[encodings[i]] = i;
 
+/**
+ * Reassigns the .name property of a function.
+ * Should be used when function can't be initially defined with desired name
+ * or when desired name should include `#`, `[`, `]`, etc.
+ * @param {string | symbol} name
+ * @param {Function} fn
+ * @param {object} [descriptor]
+ * @returns {Function} the same function, renamed
+ */
+function assignFunctionName(name, fn, descriptor = kEmptyObject) {
+  if (typeof name !== 'string') {
+    const symbolDescription = SymbolPrototypeGetDescription(name);
+    assert(symbolDescription !== undefined, 'Attempted to name function after descriptionless Symbol');
+    name = `[${symbolDescription}]`;
+  }
+  return ObjectDefineProperty(fn, 'name', {
+    __proto__: null,
+    writable: false,
+    enumerable: false,
+    configurable: true,
+    ...ObjectGetOwnPropertyDescriptor(fn, 'name'),
+    ...descriptor,
+    value: name,
+  });
+}
+
 module.exports = {
   getLazy,
   assertCrypto,
   assertTypeScript,
+  assignFunctionName,
   cachedResult,
   convertToValidSignal,
   createClassWrapper,
diff --git a/test/parallel/test-internal-util-helpers.js b/test/parallel/test-internal-util-helpers.js
@@ -4,7 +4,7 @@
 require('../common');
 const assert = require('assert');
 const { types } = require('util');
-const { isError } = require('internal/util');
+const { assignFunctionName, isError } = require('internal/util');
 const vm = require('vm');
 
 // Special cased errors. Test the internal function which is used in
@@ -35,3 +35,30 @@ const vm = require('vm');
   assert(!(differentRealmErr instanceof Error));
   assert(isError(differentRealmErr));
 }
+
+{
+  const nameMap = new Map([
+    [ 'meaningfulName', 'meaningfulName' ],
+    [ '', '' ],
+    [ Symbol.asyncIterator, '[Symbol.asyncIterator]' ],
+    [ Symbol('notWellKnownSymbol'), '[notWellKnownSymbol]' ],
+  ]);
+  for (const fn of [
+    () => {},
+    function() {},
+    function value() {},
+    ({ value() {} }).value,
+    new Function(),
+    Function(),
+    function() {}.bind(null),
+    class {},
+    class value {},
+  ]) {
+    for (const [ stringOrSymbol, expectedName ] of nameMap) {
+      const namedFn = assignFunctionName(stringOrSymbol, fn);
+      assert.strictEqual(fn, namedFn);
+      assert.strictEqual(namedFn.name, expectedName);
+      assert.strictEqual(namedFn.bind(null).name, `bound ${expectedName}`);
+    }
+  }
+}
