如何检查嵌套属性是否存在？

Question

检查嵌套属性是否存在的正确方法是什么？

if (openResult.notification) {
      if (openResult.notification.payload) {
        if (openResult.notification.payload.additionalData) {
          if (openResult.notification.payload.additionalData.sensorOpenWarning) {
            // now do sth with openResult.notification.payload.additionalData
          }
        }
      }
    }

Answer 1

使用try catch

var obj;

try{
  console.log(obj.one.two.three.four)
}catch(e){
  console.log("obj is undefined")
}

Answer 2

您可以使用此缩写形式：

const prop2 = ((obj || {}).prop1 || {}).prop2;

应用于您的代码将是：

const sensorOpenWarning = ((openResult || {}).notification || {}).payload || {}).additionalData || {}).sensorOpenWarning;