CORS - PHP + JavaScript

fetch.js

const url = "";
const options = {
      credentials: 'include',
      mode: 'cors'  
}

fetch(url, options)
  .then(res => res.json())
  .then((json) => {
    console.log(json)
  })
  .catch(error => {
    console.info(error)
  })
}

header.php

<?php

header("Access-Control-Allow-Origin: http://localhost:3000");
header("Access-Control-Allow-Credentials: true");
header("Content-Type: application/json; charset=utf-8");
header("Access-Control-Allow-Methods: GET,POST,HEAD,OPTIONS");