Send JSON back as response, status code 0

Developers Workers
1

Hello, I am new to using workers. I wanted to make a demo function for myself and have tripped up sending a response back to the client. Im not sure if its a worker issue or client side error.

The worker receives 2 numbers and returns the sum. everything seems to work on the worker side

addEventListener('fetch', event => {
  if(event.request.method === 'POST'){
    event.respondWith(handleRequest(event.request))
   }
})

/**
 * Respond to the request
 * @param {Request} request
 */

const addNumbers = (first, second) => {
    const total = first + second;
    return total;
} 

async function handleRequest(request) {
  const { numOne, numTwo } = await request.json();

  const data = {
      total: addNumbers(numOne, numTwo)
  }

  const init = {
    headers: {
      'content-type': 'application/json;charset=UTF-8',
    },
  }
  return new Response( JSON.stringify(data), init)
}

This returns

200 OK
content-length:
11
content-type:
application/json;charset=UTF-8
{"total":3}

On my client side

document.getElementById("form").addEventListener("submit", function (event) {
  const numOne = document.getElementById("num-one").value;
  const numTwo = document.getElementById("num-two").value;

  const data = {
    numOne,
    numTwo,
  };

  fetch("https://xxxxxxxxx.xxxx.workers.dev/", {
    method: "POST",
    mode: "no-cors",
    headers: {
      "Content-Type": "application/json",
    },

    body: JSON.stringify(data),

  }).then(function (response) {
    console.log(response);
  });

  event.preventDefault();

});

I log this 0

What am I doing wrong?