NodeJS中使用Mongoose如何将MongoDB查询返回数组转为指定字符串

直接通过数组的map+join方法即可完成转换，逻辑如下：

1. 用map遍历原数组，提取每个元素的scholarship_type属性值，生成纯字符串数组
2. 用join指定分隔符为, （逗号加空格）拼接为目标字符串

示例代码如下：

// resultArray为你从Mongoose查询得到的结果数组
const targetStr = resultArray.map(item => item.scholarship_type).join(', ');

完整测试示例：

const resultArray = [ 
  { scholarship_type: 'Archer Achiever Scholarship' },
  { scholarship_type: 'Star Scholarship' },
  { scholarship_type: 'Star Scholarship' },
  { scholarship_type: 'Archer Achiever Scholarship' },
  { scholarship_type: 'Star Scholarship' },
  { scholarship_type: 'Archer Achiever Scholarship' }
];

const targetStr = resultArray.map(item => item.scholarship_type).join(', ');
// 输出结果完全符合需求："Archer Achiever Scholarship, Star Scholarship, Star Scholarship, Archer Achiever Scholarship, Star Scholarship, Archer Achiever Scholarship"

内容的提问来源于stack exchange，提问作者Rollo