JXSoftTools/Assets/JsonIOTools/JsonIOEditor.cs

using System.Collections;
using System.Collections.Generic;
using UnityEditor;
using UnityEngine;

#if UNITY_EDITOR
public class JsonIOEditor : EditorWindow
{
    public TextAsset JsonSaved;

    [MenuItem("JXSoft/JsonIOTools/JsonLoader")]
    static void Init()
    {
        var window = GetWindow<JsonIOEditor>();
        window.Show();
    }

    void OnGUI()
    {
        JsonSaved = (TextAsset)EditorGUILayout.ObjectField("SaveData", JsonSaved,typeof(TextAsset), true);
    }
}
#endif