using System;

using System.Text.Json;

using System.Collections.Generic;

​

​

var str = "{\"data\":[],\"totalChange\":0}";

var test = JsonSerializer.Deserialize<Sparkline>(str);

Console.WriteLine(test.totalChange);

Console.WriteLine(test.data.Count);

​

​

public class Sparkline

{

    public List<double> data { get; set; }

    public double totalChange { get; set; }

}