State is read-only • ঢ়ଶͷมߋجຊతʹͰ͖ͳ͍ɺมߋ͢ΔͷReducerͷΈɻ • (state, action) => newState • ͔͠ Reducer ͕ͬͯΔͷঢ়ଶͷ"มߋ"Ͱͳ͍ɻݫີʹɺ৽͍͠ঢ়ଶΛ࡞ͬͯ Ϛοϐϯά͢Δʹ͍͠ɻ༰Λॻ͖͚͑ͨͩͰreduxมߋͨ͠ͱೝΊͯ͘Ε ͣɺ৽͍͠ΦϒδΣΫτΛฦ͢ඞཁ͕͋Δ ؆୯ʹݴͬͯ͠·͑ঢ়ଶͷ͕͍͢͠ɻ ్த͔Βউखʹঢ়ଶ͕ॻ͖͑ΒΕΔ͜ͱ͕ͳ͍ͷͰ σόοά͍͢͠ʢredux-devtoolsʣ