i am trying to commit a simple mutation but it isn't working

import { createStore } from 'vuex'
import axios from 'axios';
export default createStore({
  state: {
    user:{
    }
  },
  mutations: {
    change_user(state ,payload) {
      state.user = payload;
    }
  },
  actions: {
   async get_data({commit}){
      let result = await  axios.get('http://localhost:3000/posts/');
      commit('change_user',result.data);

    }
  },
  modules: {
  }
})

but commit('change_user',result.data); seems to be not working

response : {balance: 32323, withdrawls: 23, earned_today: 3223, refers: 2323}

is something wrong in my code?