Example.cs

using UnityEngine;

public class Example : MonoBehaviour
{
    private Vector3 m_prevLocalPosition;

    private enum DirectionType
    {
        NONE,
        UP,
        DOWN,
        LEFT,
        RIGHT
    }

    private void Awake()
    {
        m_prevLocalPosition = transform.localPosition;
    }

    private void LateUpdate()
    {
        var movement = transform.localPosition - m_prevLocalPosition;

        var directionType =
                0.1f < movement.magnitude
                    ? Mathf.Abs( movement.y ) < Mathf.Abs( movement.x )
                        ? 0 < movement.x
                            ? DirectionType.RIGHT
                            : DirectionType.LEFT
                        : 0 < movement.y
                            ? DirectionType.UP
                            : DirectionType.DOWN
                    : DirectionType.NONE
            ;

        m_prevLocalPosition = transform.localPosition;

        Debug.Log( directionType );
    }
}