Edit in JSFiddle

/* Vue.component('component-plus', {
  template: '#plusComponent',
  props: ['count', 'plus'],
  methods: {
    plus: function() {
      this.count +=1
    }
  }
}); */

Vue.component('component-plus', {
	template: `
  	<button @click="plus">
    	我被按了 {{ compoCount }} 下
  	</button>
  `,
  props: {
  	compoCount: String
  },
  methods: {
  	plus: function() {
      this.compoCount +=1
    }
  }
})

let vm = new Vue({
	el: '#app',
 	data: {
    count: 0
  },
})

<div id="app">
  <component-plus 
    :compo-count="count" 
  >  
  </component-plus>
</div>

<!-- <script type=text/x-template id="plusComponent">
  <button @click="plus">
    我被按了 {{ count }} 下
  </button>
</script> -->