Well I mean would you rather have this:

    method(state){
        return doSomething(state)
    }

Or this:

   class A:
       otherThingThatMutatesState1()
       otherThingThatMutatesState2()
       otherThingThatMutatesState3()

       method(){
          this.state += 1 // or some other mutation
       }