title: Default value for vuex action payload?
body: <p>I'm trying to come up with a nicer way to have a default value for a vuex action payload property, right now I'm using an if-else to check if the passed payload object has a delay property, if it doesn't I set the value to default and you can imagine the rest.</p>
  
  <p>Is there a nicer way to do this in fewer lines? I'm sure there must be.</p>
  
  <p>Here is my action:</p>
  
  <pre><code>showModal ( {commit}, modalPayload ) {
  
          let delay;
  
          if(modalPayload.delay == undefined){
              delay = 3000;
          }
          else{
              delay = modalPayload.delay
          }
  
          commit('SHOW_MODAL',  modalPayload);
          setTimeout(function(){
              commit('HIDE_MODAL');
          }, delay);
  
      },
  </code></pre>
  
  <p>Thanks in advance.</p>