diff --git a/.gitignore b/.gitignore
index 0520ab8..b930c26 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,6 @@
 .vscode
 .gradle
+.ignore
 out
 build
 bin
diff --git a/files.txt b/files.txt
deleted file mode 100644
index 68c8009..0000000
--- a/files.txt
+++ /dev/null
@@ -1,144 +0,0 @@
-src/me/topchetoeu/jscript/compilation/AssignableStatement.java
-src/me/topchetoeu/jscript/compilation/CompileOptions.java
-src/me/topchetoeu/jscript/compilation/CompoundStatement.java
-src/me/topchetoeu/jscript/compilation/control/BreakStatement.java
-src/me/topchetoeu/jscript/compilation/control/ContinueStatement.java
-src/me/topchetoeu/jscript/compilation/control/DebugStatement.java
-src/me/topchetoeu/jscript/compilation/control/DeleteStatement.java
-src/me/topchetoeu/jscript/compilation/control/DoWhileStatement.java
-src/me/topchetoeu/jscript/compilation/control/ForInStatement.java
-src/me/topchetoeu/jscript/compilation/control/ForStatement.java
-src/me/topchetoeu/jscript/compilation/control/IfStatement.java
-src/me/topchetoeu/jscript/compilation/control/ReturnStatement.java
-src/me/topchetoeu/jscript/compilation/control/SwitchStatement.java
-src/me/topchetoeu/jscript/compilation/control/ThrowStatement.java
-src/me/topchetoeu/jscript/compilation/control/TryStatement.java
-src/me/topchetoeu/jscript/compilation/control/WhileStatement.java
-src/me/topchetoeu/jscript/compilation/DiscardStatement.java
-src/me/topchetoeu/jscript/compilation/Instruction.java
-src/me/topchetoeu/jscript/compilation/Statement.java
-src/me/topchetoeu/jscript/compilation/values/LazyOrStatement.java
-src/me/topchetoeu/jscript/compilation/values/ArrayStatement.java
-src/me/topchetoeu/jscript/compilation/values/CallStatement.java
-src/me/topchetoeu/jscript/compilation/values/ChangeStatement.java
-src/me/topchetoeu/jscript/compilation/values/CommaStatement.java
-src/me/topchetoeu/jscript/compilation/values/ConstantStatement.java
-src/me/topchetoeu/jscript/compilation/values/FunctionStatement.java
-src/me/topchetoeu/jscript/compilation/values/GlobalThisStatement.java
-src/me/topchetoeu/jscript/compilation/values/IndexAssignStatement.java
-src/me/topchetoeu/jscript/compilation/values/IndexStatement.java
-src/me/topchetoeu/jscript/compilation/values/LazyAndStatement.java
-src/me/topchetoeu/jscript/compilation/values/NewStatement.java
-src/me/topchetoeu/jscript/compilation/values/ObjectStatement.java
-src/me/topchetoeu/jscript/compilation/values/OperationStatement.java
-src/me/topchetoeu/jscript/compilation/values/RegexStatement.java
-src/me/topchetoeu/jscript/compilation/values/TernaryStatement.java
-src/me/topchetoeu/jscript/compilation/values/TypeofStatement.java
-src/me/topchetoeu/jscript/compilation/values/VariableAssignStatement.java
-src/me/topchetoeu/jscript/compilation/values/VariableIndexStatement.java
-src/me/topchetoeu/jscript/compilation/values/VariableStatement.java
-src/me/topchetoeu/jscript/compilation/values/VoidStatement.java
-src/me/topchetoeu/jscript/compilation/VariableDeclareStatement.java
-src/me/topchetoeu/jscript/engine/frame/CodeFrame.java
-src/me/topchetoeu/jscript/engine/frame/ConvertHint.java
-src/me/topchetoeu/jscript/engine/frame/InstructionResult.java
-src/me/topchetoeu/jscript/engine/frame/Runners.java
-src/me/topchetoeu/jscript/engine/BreakpointData.java
-src/me/topchetoeu/jscript/engine/CallContext.java
-src/me/topchetoeu/jscript/engine/debug/DebugServer.java
-src/me/topchetoeu/jscript/engine/debug/DebugState.java
-src/me/topchetoeu/jscript/engine/debug/handlers/DebuggerHandles.java
-src/me/topchetoeu/jscript/engine/debug/Http.java
-src/me/topchetoeu/jscript/engine/debug/HttpRequest.java
-src/me/topchetoeu/jscript/engine/debug/V8Error.java
-src/me/topchetoeu/jscript/engine/debug/V8Event.java
-src/me/topchetoeu/jscript/engine/debug/V8Message.java
-src/me/topchetoeu/jscript/engine/debug/V8Result.java
-src/me/topchetoeu/jscript/engine/debug/WebSocket.java
-src/me/topchetoeu/jscript/engine/debug/WebSocketMessage.java
-src/me/topchetoeu/jscript/engine/DebugCommand.java
-src/me/topchetoeu/jscript/engine/Engine.java
-src/me/topchetoeu/jscript/engine/modules/FileModuleProvider.java
-src/me/topchetoeu/jscript/engine/modules/Module.java
-src/me/topchetoeu/jscript/engine/modules/ModuleManager.java
-src/me/topchetoeu/jscript/engine/modules/ModuleProvider.java
-src/me/topchetoeu/jscript/engine/scope/GlobalScope.java
-src/me/topchetoeu/jscript/engine/scope/LocalScope.java
-src/me/topchetoeu/jscript/engine/scope/LocalScopeRecord.java
-src/me/topchetoeu/jscript/engine/scope/ScopeRecord.java
-src/me/topchetoeu/jscript/engine/scope/ValueVariable.java
-src/me/topchetoeu/jscript/engine/scope/Variable.java
-src/me/topchetoeu/jscript/engine/values/ArrayValue.java
-src/me/topchetoeu/jscript/engine/values/CodeFunction.java
-src/me/topchetoeu/jscript/engine/values/FunctionValue.java
-src/me/topchetoeu/jscript/engine/values/NativeFunction.java
-src/me/topchetoeu/jscript/engine/values/NativeWrapper.java
-src/me/topchetoeu/jscript/engine/values/ObjectValue.java
-src/me/topchetoeu/jscript/engine/values/SignalValue.java
-src/me/topchetoeu/jscript/engine/values/Symbol.java
-src/me/topchetoeu/jscript/engine/values/Values.java
-src/me/topchetoeu/jscript/events/Awaitable.java
-src/me/topchetoeu/jscript/events/DataNotifier.java
-src/me/topchetoeu/jscript/events/Event.java
-src/me/topchetoeu/jscript/events/FinishedException.java
-src/me/topchetoeu/jscript/events/Handle.java
-src/me/topchetoeu/jscript/events/Notifier.java
-src/me/topchetoeu/jscript/events/Observable.java
-src/me/topchetoeu/jscript/events/Observer.java
-src/me/topchetoeu/jscript/events/Pipe.java
-src/me/topchetoeu/jscript/events/WarmObservable.java
-src/me/topchetoeu/jscript/exceptions/EngineException.java
-src/me/topchetoeu/jscript/exceptions/SyntaxException.java
-src/me/topchetoeu/jscript/filesystem/File.java
-src/me/topchetoeu/jscript/filesystem/Filesystem.java
-src/me/topchetoeu/jscript/filesystem/InaccessibleFile.java
-src/me/topchetoeu/jscript/filesystem/MemoryFile.java
-src/me/topchetoeu/jscript/filesystem/Permissions.java
-src/me/topchetoeu/jscript/filesystem/PermissionsProvider.java
-src/me/topchetoeu/jscript/filesystem/PhysicalFile.java
-src/me/topchetoeu/jscript/filesystem/PhysicalFilesystem.java
-src/me/topchetoeu/jscript/interop/Native.java
-src/me/topchetoeu/jscript/interop/NativeGetter.java
-src/me/topchetoeu/jscript/interop/NativeSetter.java
-src/me/topchetoeu/jscript/interop/NativeTypeRegister.java
-src/me/topchetoeu/jscript/interop/Overload.java
-src/me/topchetoeu/jscript/interop/OverloadFunction.java
-src/me/topchetoeu/jscript/json/JSON.java
-src/me/topchetoeu/jscript/json/JSONElement.java
-src/me/topchetoeu/jscript/json/JSONList.java
-src/me/topchetoeu/jscript/json/JSONMap.java
-src/me/topchetoeu/jscript/Location.java
-src/me/topchetoeu/jscript/Main.java
-src/me/topchetoeu/jscript/MessageReceiver.java
-src/me/topchetoeu/jscript/parsing/Operator.java
-src/me/topchetoeu/jscript/parsing/ParseRes.java
-src/me/topchetoeu/jscript/parsing/Parsing.java
-src/me/topchetoeu/jscript/parsing/RawToken.java
-src/me/topchetoeu/jscript/parsing/TestRes.java
-src/me/topchetoeu/jscript/parsing/Token.java
-src/me/topchetoeu/jscript/parsing/TokenType.java
-src/me/topchetoeu/jscript/polyfills/Date.java
-src/me/topchetoeu/jscript/polyfills/Internals.java
-src/me/topchetoeu/jscript/polyfills/JSON.java
-src/me/topchetoeu/jscript/polyfills/Map.java
-src/me/topchetoeu/jscript/polyfills/Math.java
-src/me/topchetoeu/jscript/polyfills/PolyfillEngine.java
-src/me/topchetoeu/jscript/polyfills/Promise.java
-src/me/topchetoeu/jscript/polyfills/RegExp.java
-src/me/topchetoeu/jscript/polyfills/Set.java
-src/me/topchetoeu/jscript/polyfills/TypescriptEngine.java
-lib/core.ts
-lib/iterators.ts
-lib/map.ts
-lib/promise.ts
-lib/regex.ts
-lib/require.ts
-lib/set.ts
-lib/values/array.ts
-lib/values/boolean.ts
-lib/values/errors.ts
-lib/values/function.ts
-lib/values/number.ts
-lib/values/object.ts
-lib/values/string.ts
-lib/values/symbol.ts
diff --git a/src/me/topchetoeu/jscript/Main.java b/src/me/topchetoeu/jscript/Main.java
index e702f13..a13ad08 100644
--- a/src/me/topchetoeu/jscript/Main.java
+++ b/src/me/topchetoeu/jscript/Main.java
@@ -12,6 +12,7 @@ import me.topchetoeu.jscript.events.Observer;
 import me.topchetoeu.jscript.exceptions.EngineException;
 import me.topchetoeu.jscript.exceptions.SyntaxException;
 import me.topchetoeu.jscript.polyfills.PolyfillEngine;
+import me.topchetoeu.jscript.polyfills.TypescriptEngine;
 
 public class Main {
     static Thread task;
@@ -51,7 +52,7 @@ public class Main {
 
     public static void main(String args[]) {
         var in = new BufferedReader(new InputStreamReader(System.in));
-        engine = new PolyfillEngine(new File("."));
+        engine = new TypescriptEngine(new File("."));
         var scope = engine.global().globalChild();
         var exited = new boolean[1];
 
diff --git a/src/me/topchetoeu/jscript/compilation/values/ObjectStatement.java b/src/me/topchetoeu/jscript/compilation/values/ObjectStatement.java
index ecfc97a..99a0082 100644
--- a/src/me/topchetoeu/jscript/compilation/values/ObjectStatement.java
+++ b/src/me/topchetoeu/jscript/compilation/values/ObjectStatement.java
@@ -50,8 +50,8 @@ public class ObjectStatement extends Statement {
 
     public ObjectStatement(Location loc, Map<Object, Statement> map, Map<Object, FunctionStatement> getters, Map<Object, FunctionStatement> setters) {
         super(loc);
-        this.map = Map.copyOf(map);
-        this.getters = Map.copyOf(getters);
-        this.setters = Map.copyOf(setters);
+        this.map = map;
+        this.getters = getters;
+        this.setters = setters;
     }
 }
diff --git a/src/me/topchetoeu/jscript/engine/CallContext.java b/src/me/topchetoeu/jscript/engine/CallContext.java
index 41c0fd7..f787872 100644
--- a/src/me/topchetoeu/jscript/engine/CallContext.java
+++ b/src/me/topchetoeu/jscript/engine/CallContext.java
@@ -21,14 +21,16 @@ public class CallContext {
         return this;
     }
     public <T> CallContext setData(DataKey<T> key, T val) {
-        data.put(key, val);
+        if (val == null) data.remove(key);
+        else data.put(key, val);
         return this;
     }
     @SuppressWarnings("unchecked")
     public <T> T addData(DataKey<T> key, T val) {
         if (data.containsKey(key)) return (T)data.get(key);
         else {
-            data.put(key, val);
+            if (val == null) data.remove(key);
+            else data.put(key, val);
             return val;
         }
     }
diff --git a/src/me/topchetoeu/jscript/engine/frame/Runners.java b/src/me/topchetoeu/jscript/engine/frame/Runners.java
index ce78b8a..97f7818 100644
--- a/src/me/topchetoeu/jscript/engine/frame/Runners.java
+++ b/src/me/topchetoeu/jscript/engine/frame/Runners.java
@@ -532,6 +532,7 @@ public class Runners {
     }
 
     public static Object exec(DebugCommand state, Instruction instr, CodeFrame frame, CallContext ctx) throws InterruptedException {
+        // System.out.println(instr + "@" + instr.location);
         switch (instr.type) {
             case NOP: return execNop(instr, frame, ctx);
             case RETURN: return execReturn(instr, frame, ctx);
diff --git a/src/me/topchetoeu/jscript/engine/values/CodeFunction.java b/src/me/topchetoeu/jscript/engine/values/CodeFunction.java
index 9b93d96..e543728 100644
--- a/src/me/topchetoeu/jscript/engine/values/CodeFunction.java
+++ b/src/me/topchetoeu/jscript/engine/values/CodeFunction.java
@@ -25,6 +25,12 @@ public class CodeFunction extends FunctionValue {
         }
         return null;
     }
+    public String readable() {
+        var loc = loc();
+        if (loc == null) return name;
+        else if (name.equals("")) return loc.toString();
+        else return name + "@" + loc;
+    }
 
     @Override
     public Object call(CallContext ctx, Object thisArg, Object... args) throws InterruptedException {
diff --git a/src/me/topchetoeu/jscript/engine/values/ObjectValue.java b/src/me/topchetoeu/jscript/engine/values/ObjectValue.java
index 64d13f6..2daf6c5 100644
--- a/src/me/topchetoeu/jscript/engine/values/ObjectValue.java
+++ b/src/me/topchetoeu/jscript/engine/values/ObjectValue.java
@@ -205,6 +205,10 @@ public class ObjectValue {
         else return null;
     }
     protected boolean setField(CallContext ctx, Object key, Object val) throws InterruptedException {
+        if (val instanceof FunctionValue && ((FunctionValue)val).name.equals("")) {
+            ((FunctionValue)val).name = Values.toString(ctx, key);
+        }
+
         values.put(key, val);
         return true;
     }