I made a function with a fetch and it shows no errors until I run it. When I run it I get the error below. I ran it through jshint and jslint and they do not show any issues. This is pretty much a copy/paste of a function I have that works fine. Do you all see anything wrong?

Error from browser

Uncaught (in promise) SyntaxError: Unexpected end of JSON input
    at HTMLInputElement.<anonymous> (admin:429:59)

this.element.querySelector("#product-btn").addEventListener("click", async function(e) {
    // Make sure that the form isn't actually being sent.
    e.preventDefault();
    e.stopPropagation();
    form=document.getElementById('product-upload');
    const fields = {
        csrf_token: {
            input: document.getElementById('csrf_token'),
            error: document.getElementById('csrf_token-error')
        },
        title: {
            input: document.getElementById('title'),
            error: document.getElementById('title-error')
        },
        description: {
            input: document.getElementById('description'),
            error: document.getElementById('description-error')
        },
        cost: {
            input: document.getElementById('cost'),
            error: document.getElementById('cost-error')
        },
        old_cost: {
            input: document.getElementById('old_cost'),
            error: document.getElementById('old_cost-error')
        }
    };
    //This shows error in lint but it's jinja for python and works fine
    const response = await fetch('{{ url_for('main.upload_products') }}', {
      method: 'POST',
      headers: {
          'Content-Type': 'application/json'
      },
      body: JSON.stringify({
          csrf_token: fields.csrf_token.input.value,
          title: fields.title.input.value,
          description: fields.description.input.value,
          cost: fields.cost.input.value,
          old_cost: fields.old_cost.input.value
      })
    });
    //THE code below is where the error points to
    data = await response.json();
    if (response.ok) {
        myDropzone.processQueue();
    } else {
        const errors = data;
        form.classList.add('was-validated');
        Object.keys(errors).forEach((key) => {
            fields[key].input.classList.add('is-invalid');
            fields[key].error.innerHTML = errors[key][0];
        });
    }
});