HarmonyOS怎么将object对象转化json格式的字符串 不是jsonobject 是自己定义的object

const person: utilPersontype = { 
  name: 'John', 
  age: 20, 
  address: { 
    city: 'Wuhan', 
    country: 'China' 
  } 
}; 
console.info(util.format('Formatted object using %%O: %O', person))

Formatted object using %O: { name: 'John', 
age: 20, 
address: 
  { city: 'Wuhan', 
  country: 'China' } }