SOURCE

//全局filter
Vue.filter('up', function(val){
	return val.toUpperCase();
});

new Vue({
	el: '#app',
  data: {
  	title: 'hello',
    message: 'WOrLD'
  },
  
  //局部filter
  filters: {
  	upperCase: function(val){
    	return val.toUpperCase();
    },
    
    lowerCase: function(val){
    	return val.toLowerCase();
    }
  }
});

<div id="app">
  <p>{{title | upperCase}}</p>
  <p>{{message | lowerCase}}</p>
  <p>{{message | up}}</p>
</div>