如何在JS中循环一个复杂的对象答案

【问题标题】：How to loop through a complex object in JS如何在JS中循环一个复杂的对象
【发布时间】：2020-07-22 06:15:46
【问题描述】：

这是我的 obj，我只想循环显示错误：

var obj = {
    "error": {
        "errors": {
            "username": {
                "properties": {
                    "message": "username field is empty.",
                    "type": "required",
                    "path": "username"
                },
                "kind": "required",
                "path": "username"
            },
            "email": {
                "properties": {
                    "message": "email field is empty.",
                    "type": "required",
                    "path": "email"
                },
                "kind": "required",
                "path": "email"
            },
            "password": {
                "properties": {
                    "message": "password field is empty.",
                    "type": "required",
                    "path": "password"
                },
                "kind": "required",
                "path": "password"
            }
        },
        "_message": "User validation failed",
        "message": "User validation failed: username: username field is empty., email: email field is empty., password: password field is empty."
    }
}

我想显示错误：properties.message 但我很难过，这是我迄今为止尝试过的：

for (var key in obj.error.errors) {
    for (var key2 in key.properties){
        for (var key3 in key2.message){
            console.log(key3)
        } 
    } 
}

但是控制台是空白的。

【问题讨论】：

第二个和第三个 for 循环看起来有问题 :)

标签： javascript loops for-loop object

【解决方案1】：

在循环中，您获取的是密钥，而不是对象本身。此外，如果您的数据是这样的结构，您也不需要添加所有这些循环。只需挑选错误，遍历所有错误。

for(var d in obj.error.errors){
    console.log(a[d].properties.message)
}

【讨论】：

【解决方案2】：

一个可行的解决方案

Object.values(obj.error.errors).forEach((error) => { console.log(error.properties.message) })

查看您的数据结构，您只需要迭代“错误”列表

【讨论】：

【解决方案3】：

检查一下，它将以properties:message 格式返回给您

const obj = {
    "error": {
        "errors": {
            "username": {
                "properties": {
                    "message": "username field is empty.",
                    "type": "required",
                    "path": "username"
                },
                "kind": "required",
                "path": "username"
            },
            "email": {
                "properties": {
                    "message": "email field is empty.",
                    "type": "required",
                    "path": "email"
                },
                "kind": "required",
                "path": "email"
            },
            "password": {
                "properties": {
                    "message": "password field is empty.",
                    "type": "required",
                    "path": "password"
                },
                "kind": "required",
                "path": "password"
            }
        },
        "_message": "User validation failed",
        "message": "User validation failed: username: username field is empty., email: email field is empty., password: password field is empty."
    }
};

const objVal = Object.values(obj.error.errors);

const errors = objVal.reduce((obj, item) => {
  return (obj[item.path] = item.properties.message, obj)
},{})

console.log(errors);

【讨论】：