如何检查对象是否在json中？

Question

我正在使用谷歌地图自动完成功能，我正在检索字段中的每个对象，如下所示：

$("#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);

但有时我们没有部分或全部这些字段确实会发生，我们会收到以下错误：

未捕获的类型错误：无法读取未定义的属性“long_name”

我试图通过检查这些字段是否存在来做一个条件，我尝试检查 undefined 或者只是检查它是否存在：

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：

未捕获的类型错误：无法读取未定义的属性“long_name”

它指的是if中的string long_name

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);
  });

Answer 1

试试这个：

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

Answer 2

你试过了吗？

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);
}

您可能还想检查 NaN 或 null 类型。失败时使用 typeof 找出类型：

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

或

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