如何从对象数组中获取最新数据

Question

I have an array of objects and each object has updatedDate . I am trying get the latest UpdatedDateusing following lines of javascript but it returns NaN to me.

var maxDate = Math.max.apply(Math, obj.reportsArray.map(function (o)
{
    return o.UpdatedDate;
}))

What i am doing wrong here?

Answer 1

The problem is, that Math.max function requires type Numbers , and you are getting NaN when try to use it for different type of data.

You need to convert the Date object to number, alike getTime() or similar function valueOf() , and if you need to get result at Date as well - then to convert Number back to Date .

var maxDate = Math.max.apply(Math, obj.reportsArray.map(function (o)
{
    return o.UpdatedDate.valueOf(); // <-- here you need the convertion of Date object
}))