如何在JavaScript中显示键内有键的json数据？

function displayNestedKeys(jsonData) {
  for (var key in jsonData) {
    if (typeof jsonData[key] === 'object') {
      console.log(key + ":");
      displayNestedKeys(jsonData[key]);
    } else {
      console.log(key + ": " + jsonData[key]);
    }
  }
}

var jsonData = {
  "name": "John",
  "age": 30,
  "address": {
    "street": "123 Main St",
    "city": "New York",
    "country": "USA"
  }
};

displayNestedKeys(jsonData);

name: John
age: 30
address:
street: 123 Main St
city: New York
country: USA