how to fix Uncaught ReferenceError after module import

Question

I'm getting an "Uncaught ReferenceError" on an onsubmit event in a form that has previously worked before splitting up my index.js into an additional js module. Tried a few different things that did not make a difference. Is there a way to solve this?

index.html

<form name="formFill" onsubmit="submitForm()" id="form">
   <button type="submit" id="calculate">Calculate</button>
   </form>

index.js

const submitForm = (event) => {
console.log('submitForm:', here)
const form = document.getElementById('form');
const data = new FormData(form);
const dataObject = {};
for (const [key, value] of data.entries()) {
dataObject[key] = value;
}
return dataObject; 
}