JsonUtility.ToJson

Parameters

Returns

string The object's data in JSON format.

Description

Generate a JSON representation of the public fields of an object.

Internally, this method uses the Unity serializer. The object you pass in and all its fields must meet the requirements for serialization by the Unity serializer. For the full list of these requirements, refer to Serialization rules in the manual.

ToJson supports any plain class or structure and classes derived from MonoBehaviour or ScriptableObject. Other engine types are not supported. In the Editor only, you can use EditorJsonUtility.ToJson to serialize other engine types to JSON.

If the object contains fields with references to other Unity objects, those references are serialized by recording the InstanceID for each referenced object. Because the Instance ID acts like a handle to the in-memory object instance, the JSON string can only be deserialized back during the same session of the Unity engine.

Note that while ToJson acccepts primitive types, instead of serializing them directly, it attempts to serialize their public instance fields, producing an empty object as a result. Similarly, passing an array does not produce a JSON array containing each element, but an object containing the public fields of the array object itself (of which there are none). To serialize the actual content of an array or primitive type, you must wrap it in a class or struct.

ToJson can be called from background threads. You should not alter the object that you pass to this function while it is still executing.

Additional resources: MonoBehaviour, ScriptableObject, Object.GetInstanceID

using UnityEngine;

public class PlayerState : MonoBehaviour
{
    public string playerName;
    public int lives;
    public float health;

    public string SaveToString()
    {
        return JsonUtility.ToJson(this);
    }

    // Given:
    // playerName = "Dr Charles"
    // lives = 3
    // health = 0.8f
    // SaveToString returns:
    // {"playerName":"Dr Charles","lives":3,"health":0.8}
}