从JS对象将属性值重新赋值给另一个

function assignObject(source, target) {
  for (var key in source) {
    if (source.hasOwnProperty(key)) {
      var value = source[key];
      if (typeof value === 'object' && value !== null) {
        target[key] = assignObject(value, {});
      } else {
        target[key] = value;
      }
    }
  }
  return target;
}

// 示例用法
var sourceObject = {
  name: 'John',
  age: 30,
  address: {
    city: 'New York',
    country: 'USA'
  }
};

var targetObject = {};

assignObject(sourceObject, targetObject);

console.log(targetObject);