Changing sprite depending on movement direction

Hi, I'm making a 2D game where enemies chase the player, but I'm having trouble changing the enemies sprite based on the movement direction. So like if the player is to the right of the enemy, I want to change the sprite to moving_right.

So like

 // if player is to right of enemy {
         this.gameObject.GetComponent<SpriteRenderer>().sprite = moving_right;
 }

Thanks in advance!