[Vuejs]-Error in render Vuex

emphasized textIn your mutations, you are accessing the state using this.$store.state. This is wrong as this does not point to the vue instance.

The mutation handler receives the state as the first argument:

myMutation(state){
    //use state argumentt to access state
}

Here is the updated code sandbox

One more thing: mapMutations is a helper which maps component methods to store.commit calls. So they are just methods in the component Add it to methods option not the computed as they are not computing anything

Pass state as an argument in your mutations’ functions like this:

increment(state) { 
  state.stake.value += 1;
},

You don’t need to do this.$store in your store. Only in your vue components