FormsApi.getValues()

Every field's value by fully qualified name: a text field's text, a check box's or radio group's export value when one is on and 'Off' when none is, a choice field's option (a multi-select list box's choices as an array). Signature fields are left out. With a viewer open, what the viewer holds, typed values included. What it returns can be given back to setValues(); only read-only fields are refused. Needs the extract feature.

const values = await doc.forms.getValues();
await fetch('/submit', { method: 'POST', body: JSON.stringify(values) });