SOURCE

function deepClone(obj,hash = new Map()){
    if(obj===null||typeof obj!=='object'){
        return obj
    }
    if(hash.has(obj)){
        return hash.get(obj)
    }
    const clone = Array.isArray(obj)?[]:{}
    hash.set(obj,clone)
    for(let key in obj){
        if(Object.prototype.hasOwnProperty.call(obj,key)){
            clone[key] = deepClone(obj[key],hash)
        }
    }
    return clone;
}
const originalObj = {
  name: 'John',
  age: 30,
  address: {
    street: '123 Main St',
    city: 'New York'
  }
};

const clonedObj = deepClone(originalObj);

console.log(clonedObj); // 输出深拷贝后的对象
console.log(originalObj === clonedObj); // 输出 false，说明是不同的对象