如何将数组中每个对象的Subject元素转为逗号分隔字符串

可以用JavaScript的Array.prototype.map()和Array.prototype.join()方法实现需求，核心逻辑是遍历数组并转换每个对象的Subject字段：

实现步骤 #

• 遍历原数组，对每个对象做字段转换
• 提取Subject数组中所有元素的Name属性，生成新的字符串数组
• 用, （逗号加空格）拼接字符串数组，替换原对象的Subject数组

代码示例 #

// 原对象数组
const originalArray = [
    {
        "ID": "771276",       
        "Name": "John",        
        "Subject": [
            { "Name": "Subject 1" },
            { "Name": "Subject 2" }
        ]
    },
    {
        "ID": "771277",       
        "Name": "Mary",        
        "Subject": [
            { "Name": "Subject 80" }
        ]
    }
];

// 执行转换
const transformedArray = originalArray.map(item => ({
    ...item,
    Subject: item.Subject.map(sub => sub.Name).join(', ')
}));

console.log(transformedArray);

转换结果 #

[
    {
        "ID": "771276",
        "Name": "John",
        "Subject": "Subject 1, Subject 2"
    },
    {
        "ID": "771277",
        "Name": "Mary",
        "Subject": "Subject 80"
    }
]

特殊场景处理 #

如果对象的Subject是空数组，转换后会得到空字符串，比如：

// 空Subject示例对象
const emptySubjectItem = {
    "ID": "771278",
    "Name": "Bob",
    "Subject": []
};
// 转换后Subject值为""

内容的提问来源于stack exchange，提问作者S_A