sera-slackbot/Bot/Library/JsonFileReader.cs

using System.Text.Json;
using Microsoft.Extensions.Configuration;
using System.IO;
using System;

namespace sera_slackbot.Library
{
    public class JsonFileReader
    {
        private string path;
        public JsonFileReader(IConfiguration config)
        {
            path = config.GetSection("Persistence").GetValue<string>("Path");
        }

        public dynamic Read(string filename)
        {
            var filePath = path + "/" + filename;
            var text = File.ReadAllText(filePath);
            return JsonSerializer.Deserialize<dynamic>(text);
        }
    }
}