Does Thunderwave work against enemy spells?
A wave of thunderous force sweeps out from you. Each creature in a 15-foot cube originating from you ... On a failed save, a creature takes 2d8 thunder damage and is pushed 10 feet away from you. {snip} In addition, unsecured objects that are completely within the area of effect are automatically pushed 10 feet away from you by the spell’s effect ... (spell description, Basic Rules, p. 103)
For example, if I readied a reaction to cast thunderwave if a magical attack like fire bolt or fire ball headed towards me, would thunderwave send it back to sender since the ball/bolt isn't a secured object?