client/src/components/HelloWorld.vue

HelloWorld.vue

<template>
  <div class="hello">
    <a href="http://localhost:3000/auth/github">
      <button>Sign-In With Github</button>
    </a>
  </div>
</template>

<script>
import axios from "axios";

export default {
  name: 'HelloWorld',
  mounted(){
    // to get the cookie data whenever component is mounted. 
    this.checkIfLoggedIn()
  },
  methods: {
    checkIfLoggedIn() {
      axios
       .get('http://localhost:3000/auth/check')
       .then(response => {
         console.log(response.data);
      });
    }
  }
}
</script>