判断一个对象存不存在

不是非空，而是不存在

方法	描述
hasOwnProperty()	方法会返回一个布尔值，可以检测对象是否有某个属性

let obj={
    "testid": "sos1626142526677", 
    "status": "end", 
    "useraccount": "xiaofeng", 
    "start": "2021-07-13 10:15:26", 
    "end": "2021-07-13 10:15:40", 
    "videocall": 3, 
    "location": 3, 
    "alarm": 3, 
    "total": 51, 
    "comment": null, 
    "reserve": null, 
    "username": null, 
    "data": [
        {
            "testid": "sos1626142526677", 
            "status": "end", 
            "target": "B600021001", 
            "start": "2021-07-13 10:15:34", 
            "end": "2021-07-13 10:15:36", 
            "videocall": 1, 
            "location": 1, 
            "alarm": 1, 
            "reserve": null
        }, 
        {
            "testid": "sos1626142526677", 
            "status": "end", 
            "target": "A300000001", 
            "start": "2021-07-13 10:15:34", 
            "end": "2021-07-13 10:15:37", 
            "videocall": 1, 
            "location": 1, 
            "alarm": 1, 
            "reserve": null
        }, 
        {
            "testid": "sos1626142526677", 
            "status": "end", 
            "target": "A300000002", 
            "start": "2021-07-13 10:15:34", 
            "end": "2021-07-13 10:15:38", 
            "videocall": 1, 
            "location": 1, 
            "alarm": 1, 
            "reserve": null
        }
    ]
}
console.log(obj.hasOwnProperty('data')) // true