const moduleA = {
    state: {
        count: 1
    },
    mutations: {
        sayCountA(state) {
            console.log('Module A count: ', state.count);
        }
    },
    actions: {
        maAction(context) {
            context.dispatch('mbAction');
        }
    }
};

const moduleB = {
    state: {
        count: 
 
2
    },
    mutations: {
        sayCountB(state, num) {
            console.log('Module B count: ', state.count+num);
        }
    },
    action: {
        mbAction({ commit, rootState }) {
            commit('sayCountA');
            commit('sayCountB', rootState.a.count);
        }
    }
};

const store 
 
= {
    modules: {
        a: moduleA,
        b: moduleB
    }
};

store.dispatch('maAction'); // Module A count: 1、Module B count: 3