diff --git a/src/main/java/dev/exhq/ajarc/computer/ComputerBlockEntity.java b/src/main/java/dev/exhq/ajarc/computer/ComputerBlockEntity.java
index 139fe42..49156f0 100644
--- a/src/main/java/dev/exhq/ajarc/computer/ComputerBlockEntity.java
+++ b/src/main/java/dev/exhq/ajarc/computer/ComputerBlockEntity.java
@@ -5,7 +5,7 @@ import dev.exhq.ajarc.Ajar;
 import dev.exhq.ajarc.network.ComputerScreenUpdate;
 import dev.exhq.ajarc.register.Register;
 import dev.exhq.ajarc.vm.JsVm;
-import dev.exhq.ajarc.vm.WasmVm;
+//import dev.exhq.ajarc.vm.WasmVm;
 import net.minecraft.core.BlockPos;
 import net.minecraft.core.HolderLookup;
 import net.minecraft.nbt.CompoundTag;
@@ -35,6 +35,7 @@ public class ComputerBlockEntity extends BlockEntity {
 	private static final MapCodec<ComputerTerminal> screenCodec = ComputerTerminal.CODEC
 			.fieldOf("screen")
 			.setPartial(() -> ComputerTerminal.ofSize(20, 30));
+	JsVm jsVm = new JsVm();
 	private List<String> lines = new ArrayList<>();
 
 	@Override
@@ -76,7 +77,7 @@ public class ComputerBlockEntity extends BlockEntity {
 
 	public void executeCommand(String line) {
 		lines.add("$ " + line);
-		lines.add(JsVm.EvalJs(line));
+		lines.add(jsVm.evalJs(line));
 //		if (line.equals("small")) {
 //			screen = ComputerTerminal.ofSize(10, 20);
 //			lines.add("Made small!");
diff --git a/src/main/java/dev/exhq/ajarc/vm/JsVm.java b/src/main/java/dev/exhq/ajarc/vm/JsVm.java
index 3424004..6e293b4 100644
--- a/src/main/java/dev/exhq/ajarc/vm/JsVm.java
+++ b/src/main/java/dev/exhq/ajarc/vm/JsVm.java
@@ -1,25 +1,44 @@
 package dev.exhq.ajarc.vm;
 
-import dev.exhq.ajarc.computer.ComputerBlockEntity;
 import org.mozilla.javascript.Context;
 import org.mozilla.javascript.Scriptable;
 import org.mozilla.javascript.ScriptableObject;
+import org.mozilla.javascript.JavaScriptException;
 
 public class JsVm {
-	public static String EvalJs(String command){
-		var cx = Context.enter();
+	private Context cx;
+	private Scriptable scope;
+
+	public JsVm() {
+		cx = Context.enter();
 		try {
-			Scriptable scope = cx.initStandardObjects();
+			scope = cx.initStandardObjects();
 			MathJ mathJ = new MathJ();
 			Object wrappedJsVm = Context.javaToJS(mathJ, scope);
 			ScriptableObject.putProperty(scope, "mathj", wrappedJsVm);
-			Object result = cx.evaluateString(scope, command, "<cmd>", 1, null);
-
-			return Context.toString(result);
 		} finally {
 			Context.exit();
 		}
 	}
 
+	public String evalJs(String command) {
+		Context.enter();
+		try {
+			Object result = cx.evaluateString(scope, command, "<cmd>", 1, null);
+			return Context.toString(result);
+		} catch (JavaScriptException e) {
+			return e.getMessage();
+		} catch (Exception e) {
+			return e.getMessage();
+		} finally {
+			Context.exit();
+		}
+	}
 
-}
\ No newline at end of file
+	public void cleanup() {
+		if (cx != null) {
+			cx.exit();
+			cx = null;
+		}
+	}
+}
diff --git a/src/main/java/dev/exhq/ajarc/vm/WasmVm.java b/src/main/java/dev/exhq/ajarc/vm/WasmVm.java
index fb26537..73b512f 100644
--- a/src/main/java/dev/exhq/ajarc/vm/WasmVm.java
+++ b/src/main/java/dev/exhq/ajarc/vm/WasmVm.java
@@ -1,65 +1,65 @@
-package dev.exhq.ajarc.vm;
-
-import com.dylibso.chicory.runtime.HostFunction;
-import com.dylibso.chicory.runtime.HostImports;
-import com.dylibso.chicory.runtime.Instance;
-import com.dylibso.chicory.runtime.Module;
-import com.dylibso.chicory.wasm.types.Value;
-import com.dylibso.chicory.wasm.types.ValueType;
-import dev.exhq.ajarc.Ajar;
-import dev.exhq.ajarc.computer.ComputerBlockEntity;
-import dev.exhq.ajarc.computer.ComputerTerminal;
-import net.minecraft.client.Minecraft;
-
-import java.io.IOException;
-import java.util.List;
-
-public class WasmVm {
-
-	private final Instance instance;
-
-	public WasmVm(ComputerBlockEntity entity) {
-		try {
-			var setSize = new HostFunction(
-					(instance1, args) -> {
-						int rows = args[0].asInt();
-						int cols = args[1].asInt();
-						entity.setTerminal(ComputerTerminal.ofSize(rows, cols));
-						return new Value[0];
-					},
-					"env",
-					"setSize",
-					List.of(ValueType.I32, ValueType.I32),
-					List.of());
-			var inputStream = Minecraft.getInstance()
-			                           .getResourceManager()
-			                           .getResourceOrThrow(Ajar.identifier("test.wasm"))
-			                           .open();
-			var module = Module.builder(inputStream)
-			                   .withHostImports(new HostImports(
-					                   new HostFunction[]{
-							                   setSize
-					                   }
-			                   ))
-			                   .build();
-			this.instance = module.instantiate();
-		} catch (IOException e) {
-			Ajar.LOGGER.error("Could not load wasm module", e);
-			throw new RuntimeException(e);
-		}
-	}
-
-	public int add(int left, int right) {
-		var export = instance.export("add");
-		var timer = System.nanoTime();
-		for (int i = 0; i < 10000; i++) {
-			export.apply(Value.i32(left), Value.i32(right));
-		}
-		System.out.println("Took " + ((System.nanoTime() - timer) / 1_000_000) + "ms to add 1000*2 numbers");
-		var result = export.apply(Value.i32(left), Value.i32(right));
-		assert result.length == 1;
-		return result[0].asInt();
-	}
-
-
-}
+//package dev.exhq.ajarc.vm;
+//
+//import com.dylibso.chicory.runtime.HostFunction;
+//import com.dylibso.chicory.runtime.HostImports;
+//import com.dylibso.chicory.runtime.Instance;
+//import com.dylibso.chicory.runtime.Module;
+//import com.dylibso.chicory.wasm.types.Value;
+//import com.dylibso.chicory.wasm.types.ValueType;
+//import dev.exhq.ajarc.Ajar;
+//import dev.exhq.ajarc.computer.ComputerBlockEntity;
+//import dev.exhq.ajarc.computer.ComputerTerminal;
+//import net.minecraft.client.Minecraft;
+//
+//import java.io.IOException;
+//import java.util.List;
+//
+//public class WasmVm {
+//
+//	private final Instance instance;
+//
+//	public WasmVm(ComputerBlockEntity entity) {
+//		try {
+//			var setSize = new HostFunction(
+//					(instance1, args) -> {
+//						int rows = args[0].asInt();
+//						int cols = args[1].asInt();
+//						entity.setTerminal(ComputerTerminal.ofSize(rows, cols));
+//						return new Value[0];
+//					},
+//					"env",
+//					"setSize",
+//					List.of(ValueType.I32, ValueType.I32),
+//					List.of());
+//			var inputStream = Minecraft.getInstance()
+//			                           .getResourceManager()
+//			                           .getResourceOrThrow(Ajar.identifier("test.wasm"))
+//			                           .open();
+//			var module = Module.builder(inputStream)
+//			                   .withHostImports(new HostImports(
+//					                   new HostFunction[]{
+//							                   setSize
+//					                   }
+//			                   ))
+//			                   .build();
+//			this.instance = module.instantiate();
+//		} catch (IOException e) {
+//			Ajar.LOGGER.error("Could not load wasm module", e);
+//			throw new RuntimeException(e);
+//		}
+//	}
+//
+//	public int add(int left, int right) {
+//		var export = instance.export("add");
+//		var timer = System.nanoTime();
+//		for (int i = 0; i < 10000; i++) {
+//			export.apply(Value.i32(left), Value.i32(right));
+//		}
+//		System.out.println("Took " + ((System.nanoTime() - timer) / 1_000_000) + "ms to add 1000*2 numbers");
+//		var result = export.apply(Value.i32(left), Value.i32(right));
+//		assert result.length == 1;
+//		return result[0].asInt();
+//	}
+//
+//
+//}