diff --git a/src/domains/Runtime.ts b/src/domains/Runtime.ts
index b980929..67388f9 100644
--- a/src/domains/Runtime.ts
+++ b/src/domains/Runtime.ts
@@ -64,9 +64,9 @@ export function getProperties(
   return objManager.getProperties(params)
 }
 
-export function evaluate(
+export async function evaluate(
   params: Runtime.EvaluateRequest
-): Runtime.EvaluateResponse {
+): Promise<Runtime.EvaluateResponse> {
   const ret: any = {}
 
   let result: any
@@ -74,7 +74,7 @@ export function evaluate(
     if (params.throwOnSideEffect && hasSideEffect(params.expression)) {
       throw EvalError('Possible side-effect in debug-evaluate')
     }
-    result = evaluateJs(params.expression)
+    result = await evaluateJs(params.expression)
     setGlobal('$_', result)
     ret.result = objManager.wrap(result, {
       generatePreview: true,
diff --git a/src/index.ts b/src/index.ts
index 1dd6e97..0ea8300 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -38,7 +38,6 @@ chobitsu.register('Runtime', {
   discardConsoleEntries: noop,
   getHeapUsage: noop,
   getIsolateId: noop,
-  releaseObject: noop,
   releaseObjectGroup: noop,
   runIfWaitingForDebugger: noop,
 })
diff --git a/src/lib/evaluate.ts b/src/lib/evaluate.ts
index 0732a13..f0abcce 100644
--- a/src/lib/evaluate.ts
+++ b/src/lib/evaluate.ts
@@ -44,14 +44,14 @@ export function setGlobal(name: string, val: any) {
   global[name] = val
 }
 
-export default function evaluate(expression: string) {
+export default async function evaluate(expression: string) {
   let ret
 
   injectGlobal()
   try {
-    ret = eval.call(window, `(${expression})`)
+    ret = await eval.call(window, `(async() => (${expression}))()`)
   } catch (e) {
-    ret = eval.call(window, expression)
+    ret = await eval.call(window, `(async () => {${expression}})()`)
   }
   clearGlobal()
 
diff --git a/src/lib/objManager.ts b/src/lib/objManager.ts
index ff6a9e3..d79cdd6 100644
--- a/src/lib/objManager.ts
+++ b/src/lib/objManager.ts
@@ -46,6 +46,10 @@ export function wrap(
   value: any,
   { generatePreview = false, self = value } = {}
 ): any {
+  if (typeof value === 'object' && value !== null && typeof value.toJSON === 'function') {
+    value = value.toJSON()
+  }
+
   const ret = basic(value)
   const { type, subtype } = ret