Javascript 如何检查对象是否在json中？

我正在使用google maps autocomplete，并在如下字段中检索每个对象：

$("#usp-custom-21").val(arrAddress.filter(x => x.types.includes("route"))[0].long_name);
$("#usp-custom-22").val(arrAddress.filter(x => x.types.includes("street_number"))[0].long_name);
$("#usp-custom-23").val(arrAddress.filter(x => x.types.includes("locality"))[0].long_name);
$("#usp-custom-8").attr("value", arrAddress.filter(x => x.types.includes("country"))[0].long_name);
$("#usp-custom-25").val(arrAddress.filter(x => x.types.includes("postal_code"))[0].long_name);

但有时确实会出现这样的情况，我们没有这些字段中的一些或所有字段，我们会得到以下错误：

未捕获的TypeError:无法读取未定义的属性“long_name”

我尝试通过检查这些字段是否存在来执行条件设置，我尝试了检查未定义的字段或简单地检查是否存在：

if(arrAddress.filter(x => x.types.includes("route"))[0] != "undefined") {
   $("#usp-custom-21").val(arrAddress.filter(x => x.types.includes("route"))[0].long_name);
}
if(arrAddress.filter(x => x.types.includes("street_number"))[0].long_name){
   $("#usp-custom-22").val(arrAddress.filter(x => x.types.includes("street_number"))[0].long_name);
}

但我仍然得到：

未捕获的TypeError:无法读取未定义的属性“long_name”

它指的是if中的字符串long_名称

完整代码：

  autocomplete.addListener('place_changed', function() {
    var place = autocomplete.getPlace();
    if (!place.geometry) {
      return;
    }
    if (place.geometry.viewport) {
      map.fitBounds(place.geometry.viewport);
    } else {
      map.setCenter(place.geometry.location);
    }
    marker.setPosition(place.geometry.location);
    currentLatitude = place.geometry.location.lat();
    currentLongitude = place.geometry.location.lng();
    var arrAddress = place.address_components;
    var Newlat = map.getCenter().lat();
    var NewLong = map.getCenter().lng();
    $("#usp-custom-19").val(parseInt(Newlat));
    $("#usp-custom-20").val(parseInt(NewLong));
    if(arrAddress.filter(x => x.types.includes("route"))[0] != "undefined") {
      $("#usp-custom-21").val(arrAddress.filter(x => x.types.includes("route"))[0].long_name);
    }
    if(arrAddress.filter(x => x.types.includes("street_number"))[0].long_name){
      $("#usp-custom-22").val(arrAddress.filter(x => x.types.includes("street_number"))[0].long_name);
    }
    if(arrAddress.filter(x => x.types.includes("locality"))[0].long_name) {
      $("#usp-custom-23").val(arrAddress.filter(x => x.types.includes("locality"))[0].long_name);
    }
    if(arrAddress.filter(x => x.types.includes("country"))[0].long_name) {
      $("#usp-custom-8").val(arrAddress.filter(x => x.types.includes("country"))[0].long_name);
    }
    if(arrAddress.filter(x => x.types.includes("postal_code"))[0].long_name) {
      $("#usp-custom-25").val(arrAddress.filter(x => x.types.includes("postal_code"))[0].long_name);
    }
    if(place.formatted_address) {
      $("#usp-custom-60").val(place.formatted_address);
    }
    $("#usp-custom-90").val(Newlat+","+NewLong);
    console.log(place.formatted_address);
  });

试试这个：

你试过这个吗

if(arrAddress.filter(x => x.types.includes("route"))[0].long_name != "undefined") {
   $("#usp-custom-21").val(arrAddress.filter(x => x.types.includes("route"))[0].long_name);
}

您可能还需要检查NaN或null类型。当类型失败时，使用typeof确定类型：

console.log(typeof x.types.includes("route"))[0])

或

---

我不知道为什么是否决票，但它是通过检查未定义的，没有引号。如果有人能告诉我为什么这个答案不正确，我将不胜感激如果你已经解答了这个问题，请将它标记为已更正。我会尽快更正。是的，只有未定义的，没有引号的，按照其他答案工作。不好意思，我错过了这些引号还有console.logtypeof x.types.includeRoute[0]是否给出未捕获的引用错误：x未定义您是否将其放入闭包中？

console.log(typeof x.types.includes("route"))[0])

console.log(typeof x.types.includes("route"))[0].long_name)