evershade/Assets/Scripts/Managers/SaveManager.cs

using System;
using System.IO;
using Managers;
using UnityEngine;
using Random = UnityEngine.Random;

[Serializable]
public class GameState
{
    public PlayerData playerData;
}

public class SaveManager : MonoBehaviour
{
    public GameState gameState;
    public PlayerData defaultPlayerData;

    private void Awake()
    {
        gameState = new GameState();
    }

    public void SaveGame()
    {
        gameState.playerData.currentMap = MapManager.Instance.currentMap.name;
        gameState.playerData.currentPosition = PlayerManager.Instance.transform.position;

        var json = JsonUtility.ToJson(gameState);
        File.WriteAllText(Application.persistentDataPath + "/gameState.json", json);
    }

    public void LoadGame(GameState gs)
    {
        gameState = gs;
        PlayerManager.Instance.LoadPlayerData(gameState.playerData);
        MapManager.Instance.GetMap(gameState.playerData.currentMap);

        /*var path = Application.persistentDataPath + "/gameState.json";
                if (File.Exists(path))
                {
                    var json = File.ReadAllText(path);
                    gameState = JsonUtility.FromJson<GameState>(json);
        }*/
    }

    public void LoadGame()
    {
        var path = Application.persistentDataPath + "/gameState.json";
        if (File.Exists(path))
        {
            var json = File.ReadAllText(path);
            gameState = JsonUtility.FromJson<GameState>(json);
        }
    }

    public void NewGame()
    {
        gameState.playerData = defaultPlayerData;
        // add items to inventory
        for (var i = 0; i < 10; i++)
        {
            // set slot to random item
            var item = GameItemManager.Instance.gameItems[
                Random.Range(0, GameItemManager.Instance.gameItems.Count - 1)];
            gameState.playerData.AddItemToInventory(item);
        }

        LoadGame(gameState);
    }
}