What is the exact use of => (arrow) operator in vue.js? [duplicate]

I am from PHP background and a newbie to js languages. Generally programmers use '=>' operator to key/value exchange in coding. But in vue js, it is little bit confusing or can't I understand the same array thing? or how it can be understood? I haven't pasted the seed.js. Just assume it has array.

<article v-for="tubmission in sortedSubmissions"
         v-bind:key="tubmission.id" class="media">

new Vue({
  el: '#app',
  data: {
    tubmissions: Seed.submissions
  },
  computed: {
    sortedSubmissions () {
      return this.tubmissions.sort((a, b) => {
        return b.votes - a.votes
      });
    }
  }
});