Synchronizing return type Vuex module and action?

Question

typescript

export default class LayoutDefault extends Vue {
    @user.Action
    public emailTest!: (test: string) => void
// or?
    public emailTest!: (test: string) => Promise<object>


    public mounted(): void {
        console.log(this.emailTest('test2')); // Promise  в любом случае

for this method

@MutationAction
    public async emailTest(test: string): Promise<object> {
        return {email: test};
    }

or separate

@Mutation
    public setEmail(email: string): void {
        this.email = email
    }

    @Action
    public updateName(email: string): void {
        this.context.commit('setEmail', email)
    }

In both cases, whether the action is async or not, and the return type of the action also does not wag, console.log always prints a Promise .

So the questions arose, which return type should be indicated then and where, how to synchronize them?
After all, in fact, there is always a Promise for methods or some other closure. And you also need to specify the same type in 2 places, the return type of the method and in the component when declaring the method

@user.Action
    public emailTest!: (test: string) => Promise<object>