javascript-obfuscator · sanex3339 · Mar 22, 2026 · Mar 22, 2026
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -3,6 +3,7 @@ Change Log
 v5.4.0
 ---
 * Add support for `import attributes`. Fixes https://github.com/javascript-obfuscator/javascript-obfuscator/issues/1256
+* Fixed `reservedNames` not preserving class method and property names when `stringArray` or `deadCodeInjection` is enabled. Fixes https://github.com/javascript-obfuscator/javascript-obfuscator/issues/1279
 * Replaced `mkdirp` dependency with native `fs.mkdirSync({ recursive: true })`. Fixes https://github.com/javascript-obfuscator/javascript-obfuscator/issues/1275. Thank you https://github.com/roli-lpci!
 
 v5.3.1

diff --git a/src/node-transformers/converting-transformers/ClassFieldTransformer.ts b/src/node-transformers/converting-transformers/ClassFieldTransformer.ts
@@ -12,6 +12,7 @@ import { NodeTransformationStage } from '../../enums/node-transformers/NodeTrans
 import { AbstractNodeTransformer } from '../AbstractNodeTransformer';
 import { NodeFactory } from '../../node/NodeFactory';
 import { NodeGuards } from '../../node/NodeGuards';
+import { IdentifierReplacer } from '../rename-identifiers-transformers/replacer/IdentifierReplacer';
 
 /**
  * replaces:
@@ -89,6 +90,18 @@ export class ClassFieldTransformer extends AbstractNodeTransformer {
         return classFieldNode;
     }
 
+    /**
+     * @param {string} name
+     * @returns {boolean}
+     */
+    private isIgnoredName(name: string): boolean {
+        if (name === ClassFieldTransformer.ignoredName) {
+            return true;
+        }
+
+        return IdentifierReplacer.isReservedName(name, this.options.reservedNames);
+    }
+
     /**
      * @param {MethodDefinition | PropertyDefinition} classFieldNode
      * @param {Identifier} keyNode
@@ -98,7 +111,7 @@ export class ClassFieldTransformer extends AbstractNodeTransformer {
         classFieldNode: ESTree.MethodDefinition | ESTree.PropertyDefinition,
         keyNode: ESTree.Identifier
     ): ESTree.MethodDefinition | ESTree.PropertyDefinition {
-        if (keyNode.name !== ClassFieldTransformer.ignoredName && !classFieldNode.computed) {
+        if (!this.isIgnoredName(keyNode.name) && !classFieldNode.computed) {
             classFieldNode.computed = true;
             classFieldNode.key = NodeFactory.literalNode(keyNode.name);
         }
@@ -115,11 +128,7 @@ export class ClassFieldTransformer extends AbstractNodeTransformer {
         classFieldNode: ESTree.MethodDefinition | ESTree.PropertyDefinition,
         keyNode: ESTree.Literal
     ): ESTree.MethodDefinition | ESTree.PropertyDefinition {
-        if (
-            typeof keyNode.value === 'string' &&
-            keyNode.value !== ClassFieldTransformer.ignoredName &&
-            !classFieldNode.computed
-        ) {
+        if (typeof keyNode.value === 'string' && !this.isIgnoredName(keyNode.value) && !classFieldNode.computed) {
             classFieldNode.computed = true;
         }
 

diff --git a/src/node-transformers/rename-identifiers-transformers/replacer/IdentifierReplacer.ts b/src/node-transformers/rename-identifiers-transformers/replacer/IdentifierReplacer.ts
@@ -52,6 +52,21 @@ export class IdentifierReplacer implements IIdentifierReplacer {
         this.identifierNamesGenerator = identifierNamesGeneratorFactory(options);
     }
 
+    /**
+     * @param {string} name
+     * @param {string} reservedNames
+     * @returns {boolean}
+     */
+    public static isReservedName(name: string, reservedNames: string[]): boolean {
+        if (!reservedNames.length) {
+            return false;
+        }
+
+        return reservedNames.some((reservedName: string) => {
+            return new RegExp(reservedName, 'g').exec(name) !== null;
+        });
+    }
+
     /**
      * Store identifier node `name` of global identifiers as key in map with random name as value.
      * Reserved name will be ignored.
@@ -62,7 +77,7 @@ export class IdentifierReplacer implements IIdentifierReplacer {
     public storeGlobalName(identifierNode: ESTree.Identifier, lexicalScopeNode: TNodeWithLexicalScope): void {
         const identifierName: string = identifierNode.name;
 
-        if (this.isReservedName(identifierName)) {
+        if (IdentifierReplacer.isReservedName(identifierName, this.options.reservedNames)) {
             return;
         }
 
@@ -89,7 +104,7 @@ export class IdentifierReplacer implements IIdentifierReplacer {
     public storeLocalName(identifierNode: ESTree.Identifier, lexicalScopeNode: TNodeWithLexicalScope): void {
         const identifierName: string = identifierNode.name;
 
-        if (this.isReservedName(identifierName)) {
+        if (IdentifierReplacer.isReservedName(identifierName, this.options.reservedNames)) {
             return;
         }
 
@@ -142,18 +157,4 @@ export class IdentifierReplacer implements IIdentifierReplacer {
     ): void {
         this.identifierNamesGenerator.preserveNameForLexicalScope(identifierNode.name, lexicalScopeNode);
     }
-
-    /**
-     * @param {string} name
-     * @returns {boolean}
-     */
-    private isReservedName(name: string): boolean {
-        if (!this.options.reservedNames.length) {
-            return false;
-        }
-
-        return this.options.reservedNames.some((reservedName: string) => {
-            return new RegExp(reservedName, 'g').exec(name) !== null;
-        });
-    }
 }
diff --git a/...ransformers/converting-transformers/class-field-transformer/ClassFieldTransformer.spec.ts b/...ransformers/converting-transformers/class-field-transformer/ClassFieldTransformer.spec.ts
@@ -273,4 +273,31 @@ describe('ClassFieldTransformer', () => {
             });
         });
     });
+
+    describe('Variant #3: class method not obfuscated if option `reservedNames` is set', () => {
+        const samplesCount: number = 100;
+
+        let obfuscations: string[];
+
+        beforeEach(() => {
+            obfuscations = [];
+            const code: string = readFileAsString(__dirname + '/fixtures/class-with-function.js');
+
+            for (let i = 0; i < samplesCount; i++) {
+                const obfuscatedCode: string = JavaScriptObfuscator.obfuscate(code, {
+                    controlFlowFlattening: true,
+                    deadCodeInjection: true,
+                    reservedNames: ['bar']
+                }).getObfuscatedCode();
+
+                obfuscations.push(obfuscatedCode);
+            }
+        });
+
+        it('class should always have `bar` method not obfuscated', () => {
+            for (const codeAsString of obfuscations) {
+                assert.match(codeAsString, /\bbar\s*\(/);
+            }
+        });
+    });
 });
diff --git a/...nsformers/converting-transformers/class-field-transformer/fixtures/class-with-function.js b/...nsformers/converting-transformers/class-field-transformer/fixtures/class-with-function.js
@@ -0,0 +1,6 @@
+class Foo {
+    bar() {
+        console.log(1);
+        baz();
+    }
+}
diff --git a/...ansformers/rename-identifiers-transformers/identifier-replacer/IdentifierReplacer.spec.ts b/...ansformers/rename-identifiers-transformers/identifier-replacer/IdentifierReplacer.spec.ts
@@ -25,7 +25,7 @@ describe('IdentifierReplacer', () => {
             });
         });
 
-        describe('Variant #1: ignore global reserved names', () => {
+        describe('Variant #2: ignore global reserved names', () => {
             let obfuscatedCode: string;
 
             before(() => {
-Original file line number
+Diff line change
@@ Expand Up / @@ -3,6 +3,7 @@ Change Log @@
     v5.4.0
     ---
     * Add support for `import attributes`. Fixes https://github.com/javascript-obfuscator/javascript-obfuscator/issues/1256
+    * Fixed `reservedNames` not preserving class method and property names when `stringArray` or `deadCodeInjection` is enabled. Fixes https://github.com/javascript-obfuscator/javascript-obfuscator/issues/1279
     * Replaced `mkdirp` dependency with native `fs.mkdirSync({ recursive: true })`. Fixes https://github.com/javascript-obfuscator/javascript-obfuscator/issues/1275. Thank you https://github.com/roli-lpci!
     v5.3.1
@@ Expand Down @@