title: Cannot read property 'commit' of undefined VUEX
body: <p>Please help me it always says Cannot read property 'commit' of undefined. Here is my code in store.js.</p>
  
  <pre><code>import Vue from 'vue';
  import Vuex from 'vuex';
  
  Vue.use(Vuex);
  
  export const store = new Vuex.Store({
    state:{
       timer: null,
       totaltime: (25 * 60)
    }, 
    mutations:{
      startTimer: (state, context) =&gt; {
      //here is the problem part I think
        state.timer = setInterval(() =&gt; context.commit('countDown'),
        1000)
      },
      countDown: state =&gt; {
        var time = state.totaltime
        if(time &gt;= 1){
          time--
        }else{
          time = 0
        }
      },
      stopTimer: state =&gt; {
        clearInterval(state.timer)
        state.timer = null
      },
      resetTimer: state =&gt; {
        state.totaltime = (25 * 60)
        clearInterval(state.timer)
      }
    },
    getters:{
        minutes: state =&gt; {
          const minutes = Math.floor(state.totaltime / 60);
          return minutes;
        },
        seconds: (state, getters) =&gt; {
          const seconds = state.totaltime - (getters.minutes * 60);
          return seconds;
        }
    },
    actions:{
  
  
    }
  })
  </code></pre>
  
  <p>I have problem it debugging. it always says like this
  'Cannot read property 'commit' of undefined'</p>
  
  <p>Here is my Timer.vue code for calling</p>
  
  <pre><code>methods: {
        formTime(time){
          return (time &lt; 10 ? '0' : '') + time;
        },
        startTimer(){
          this.resetButton = true
          this.$store.commit('startTimer')
        },
        stopTimer(){
          this.$store.commit('stopTimer')
        },
        resetTimer(){
          this.$store.commit('resetTimer')
        },
  
      },
      computed: {
        minutes(){
          var minutes = this.$store.getters.minutes;
          return this.formTime(minutes)
        },
        seconds(){
          var seconds = this.$store.getters.seconds;
          return this.formTime(seconds);
        },
        timer: {
          get(){
            return this.$store.state.timer
          }
        }
      }
  </code></pre>
  
  <p>My code in Timer.vue script computed and methods. I cannot track where the problem is... Please help me Im stuck with this here.</p>