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盘点JS判断空对象的几大方法
2022-07-07 10:07:00 【InfoQ】
知识准备
Object.keys
Object.keys()
var obj = {
name: "cxy",
age: "19"
};
var objArray = Object.getOwnPropertyNames(obj);
console.log(objArray)
objArray
Object.getOwnPropertyNames
Object.getOwnPropertyNames()
Object.getOwnPropertyNames()
Object.keys()
可枚举属性
enumerable
obj.name = "cxy"
enumerable
ture
false
for
Object.keys()
JSON.stringify()
Object.getOwnPropertyNames
Object.keys()
defineProperty
age
false
var stuObj = {
name: "cxy"
}
Object.defineProperty(stuObj, 'age', {
value: "18",
enumerable: false
});
console.log(Object.keys(stuObj))
console.log(Object.getOwnPropertyNames(stuObj))
hasOwnProperty
hasOwnProperty()
var stuObj = {
name: "cxy"
}
console.log(stuObj.hasOwnProperty('name'))
hasOwnProperty()
false
toString
盘点判空方法
JSON.stringify
判空
JSON.stringify
let obj = {
name: "cxy"
}
console.log(JSON.stringify(obj) == '{}')
for in
判空
for in
false
ture
let forNull = (items) => {
for (let item in items) {
return false
}
return true
}
Object.getOwnPropertyNames
判空
Object.getOwnPropertyNames
length
let stuArray = Object.getOwnPropertyNames(obj)
console.log(stuArray.length === 0)
Object.keys()
判空
let stuArray = Object.getOwnPropertyNames(obj)
console.log(stuArray.length === 0)
hasOwnProperty
判空
hasOwnProperty
false
let forNull = (items) => {
for (let item in items) {
if(items.hasOwnProperty(item)){
return false
}
}
return true
}
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