diff --git a/test/functional-tests/node-transformers/obfuscating-transformers/function-transformer/FunctionTransformer.spec.ts b/test/functional-tests/node-transformers/obfuscating-transformers/function-transformer/FunctionTransformer.spec.ts
index 76a9584e..9b8903f8 100644
--- a/test/functional-tests/node-transformers/obfuscating-transformers/function-transformer/FunctionTransformer.spec.ts
+++ b/test/functional-tests/node-transformers/obfuscating-transformers/function-transformer/FunctionTransformer.spec.ts
@@ -81,6 +81,40 @@ describe('FunctionTransformer', () => {
             );
             const obfuscatedCode: string = obfuscationResult.getObfuscatedCode();
 
+            const variableDeclarationMatch: RegExp = /var *(_0x[a-f0-9]{4,6}) *= *0x1;/;
+            const functionParameterMatch: RegExp = /function *\((_0x[a-f0-9]{4,6}) *= *(_0x[a-f0-9]{4,6})\) *\{/;
+            const functionBodyMatch: RegExp = /return *(_0x[a-f0-9]{4,6});/;
+
+            const variableDeclarationIdentifierName: string = obfuscatedCode.match(variableDeclarationMatch)![1];
+            const functionParameterIdentifierName: string = obfuscatedCode.match(functionParameterMatch)![1];
+            const functionDefaultParameterIdentifierName: string = obfuscatedCode.match(functionParameterMatch)![2];
+
+            const functionBodyIdentifierName: string = obfuscatedCode.match(functionBodyMatch)![1];
+
+            it('should transform function parameter assignment pattern identifier', () => {
+                assert.match(obfuscatedCode, variableDeclarationMatch);
+                assert.match(obfuscatedCode, functionParameterMatch);
+                assert.match(obfuscatedCode, functionBodyMatch);
+            });
+
+            it('should keep same names for identifier in variable declaration and default value identifier of function parameter', () => {
+                assert.equal(variableDeclarationIdentifierName, functionDefaultParameterIdentifierName);
+            });
+
+            it('should keep same names for identifiers in function params and function body', () => {
+                assert.equal(functionParameterIdentifierName, functionBodyIdentifierName);
+            });
+        });
+
+        describe('identifier as right value', () => {
+            const obfuscationResult: IObfuscationResult = JavaScriptObfuscator.obfuscate(
+                readFileAsString(__dirname + '/fixtures/assignment-pattern-as-parameter-3.js'),
+                {
+                    ...NO_CUSTOM_NODES_PRESET
+                }
+            );
+            const obfuscatedCode: string = obfuscationResult.getObfuscatedCode();
+
             const variableDeclarationMatch: RegExp = /var *(_0x[a-f0-9]{4,6}) *= *0x1;/;
             const functionParameterMatch: RegExp = /function *\((_0x[a-f0-9]{4,6}), *(_0x[a-f0-9]{4,6}) *= *(_0x[a-f0-9]{4,6})\) *\{/;
             const functionBodyMatch: RegExp = /return *(_0x[a-f0-9]{4,6}) *\+ *(_0x[a-f0-9]{4,6});/;
diff --git a/test/functional-tests/node-transformers/obfuscating-transformers/function-transformer/fixtures/assignment-pattern-as-parameter-2.js b/test/functional-tests/node-transformers/obfuscating-transformers/function-transformer/fixtures/assignment-pattern-as-parameter-2.js
index 9782200f..d48277d0 100644
--- a/test/functional-tests/node-transformers/obfuscating-transformers/function-transformer/fixtures/assignment-pattern-as-parameter-2.js
+++ b/test/functional-tests/node-transformers/obfuscating-transformers/function-transformer/fixtures/assignment-pattern-as-parameter-2.js
@@ -1,6 +1,6 @@
 (function () {
     var foo = 1;
-    var test = function (foo, bar = foo) {
-        return foo + bar;
+    var test = function (bar = foo) {
+        return bar;
     }
 })();
diff --git a/test/functional-tests/node-transformers/obfuscating-transformers/function-transformer/fixtures/assignment-pattern-as-parameter-3.js b/test/functional-tests/node-transformers/obfuscating-transformers/function-transformer/fixtures/assignment-pattern-as-parameter-3.js
new file mode 100644
index 00000000..9782200f
--- /dev/null
+++ b/test/functional-tests/node-transformers/obfuscating-transformers/function-transformer/fixtures/assignment-pattern-as-parameter-3.js
@@ -0,0 +1,6 @@
+(function () {
+    var foo = 1;
+    var test = function (foo, bar = foo) {
+        return foo + bar;
+    }
+})();