node.js 中的 NaN 替换为整数

Question

我正在使用以下代码更新 node.js

中的数据库

var mBooking = rows[0];
var distance = mBooking.distanceTravelled;
var lastLng = mBooking.lastLng;
var lastLat = mBooking.lastLat;

if(lastLat == 0)
{
    lastLat = lat;
    lastLng = lng;
}

var currentPoint = new GeoPoint(lat, lng);
var oldPoint     = new GeoPoint(lastLat, lastLng);

distance = distance + (currentPoint.distanceTo(oldPoint, true) * 1000);
if(distance == null)
    distance = 0;

var query = "UPDATE bookings SET lastLat = " + lat + ", lastLng = " + lng + ", distanceTravelled = " + distance + " WHERE id = " + mBooking.id;
console.log(query);

这是我的控制台查询

UPDATE bookings SET lastLat = 25.0979065, lastLng = 55.1634082, distanceTravelled = NaN WHERE id = 43

我如何检查距离是否为 NaN 然后我可以用 0 替换它。

现在，如果我尝试更新它会出现数据库错误

Answer 1

使用isNaN().

if (isNaN(distance))
    distance = 0;

您也可以使用 inline-if 将其压缩为一行：

distance = (isNaN(distance) ? 0 : distance);

node.js 中的 NaN 替换为整数

NaN replacement in node.js with an integer

javascript

node.js

socket.io