diff --git a/examples/basic/pages/index.tsx b/examples/basic/pages/index.tsx
index 121b81af..42fd71cb 100644
--- a/examples/basic/pages/index.tsx
+++ b/examples/basic/pages/index.tsx
@@ -39,9 +39,10 @@ const loopArray = [
 loopArray[1] = loopArray
 
 const longArray = Array.from({ length: 1000 }).map((_, i) => i)
-const map = new Map<string, any>()
+const map = new Map<any, any>()
 map.set('foo', 1)
 map.set('goo', 'hello')
+map.set({}, 'world')
 
 const set = new Set([1, 2, 3])
 
diff --git a/src/components/DataTypes/Object.tsx b/src/components/DataTypes/Object.tsx
index ec57705f..a66dc915 100644
--- a/src/components/DataTypes/Object.tsx
+++ b/src/components/DataTypes/Object.tsx
@@ -124,7 +124,9 @@ export const ObjectType: React.FC<DataItemProps<object>> = (props) => {
       if (value instanceof Map) {
         let _count = 0
         for (const item of value) {
-          const [key, value] = item
+          // fixme: key might be a object, array, or any value for the `Map<any, any>`
+          const [k, value] = item
+          const key = `${k}`
           elements.push(
             <DataKeyPair key={key} path={[...props.path, key]} value={value}
                          editable={false}/>
diff --git a/tests/index.test.tsx b/tests/index.test.tsx
index 04b5edf6..b74f957f 100644
--- a/tests/index.test.tsx
+++ b/tests/index.test.tsx
@@ -43,6 +43,17 @@ describe('render <JsonViewer/>', () => {
     render(<JsonViewer value={new Set([1, '2', 3.0, Infinity])}/>)
   })
 
+  it('render Map', () => {
+    render(
+      <JsonViewer
+        value={new Map<string, number>([['foo', 1], ['goo', 2]])}/>
+    )
+    render(
+      <JsonViewer
+        value={new Map<any, number>([[[], 1], [{}, 2]])}/>
+    )
+  })
+
   it('render object', () => {
     render(<JsonViewer value={{}}/>)
     render(<JsonViewer value={{
@@ -53,4 +64,11 @@ describe('render <JsonViewer/>', () => {
       }
     }}/>)
   })
+
+  it('render function', () => {
+    render(<JsonViewer value={function aPlusB (a: number, b: number) {
+      return a + b
+    }}/>)
+    render(<JsonViewer value={(a: number, b: number) => a + b}/>)
+  })
 })