如何检查对象的空状态答案

【问题标题】：How to check empty condition for an object如何检查对象的空状态
【发布时间】：2016-12-03 14:29:12
【问题描述】：

我有一个像下面这样的对象，但我不确定如何检查空状态我的对象，

 "general_info" : {
    "parents_name" : "",
    "date_of_birth" : "",
    "second_day_attendance" : "",
    "class_day" : "",
    "reffered_by" : "",
    "year" : "",
    "amount_paid" : "",
    "next_due" : "",
    "payment_untill" : "",
    "payment_made" : ""
},

    if(general_info == ''){
      alert('empty')
    }

我知道我错了谁能帮帮我。谢谢。

【问题讨论】：

您要检查所有属性是否为空？

标签： javascript angularjs object

【解决方案1】：

如果最终目的是检查所有属性值是否都是空字符串：

// retrieve an Array of the keys of the named Object:
Object.keys(general_info)
  // iterate over all the keys in the Array, using
  // Array.prototype.every() to see if all keys
  // match the supplied assessment:
  .every(
    // using an Arrow function to see if the current
    // property-value of the named key of the Object
    // is equal to a zero-length String:
    key => general_info[key] === ''
  );

【讨论】：

【解决方案2】：

使用Object#keys检查长度

Object.keys(general_info).length
// 10

var general_info = {
    "parents_name" : "",
    "date_of_birth" : "",
    "second_day_attendance" : "",
    "class_day" : "",
    "reffered_by" : "",
    "year" : "",
    "amount_paid" : "",
    "next_due" : "",
    "payment_untill" : "",
    "payment_made" : ""
};

if(Object.keys(general_info).length > 0){
   console.log('Object is not empty');
}

【讨论】：

【解决方案3】：

您可以使用以下方法检查对象上是否存在属性。

!Object.keys(obj).length

const general_info = {
  "parents_name": "",
  "payment_made": ""
}

const empty_object = {}

function isEmpty(obj) {
  return !Object.keys(obj).length
}

console.log(
  isEmpty(general_info)
)
console.log(
  isEmpty(empty_object) 
)

【讨论】：