Michael,
When not including an attachment form-group I receive the error "Cannot read property 'files' of undefined.
I can get around this by adding the attachment form-group and adding the inline style of display:none;.
You may want to amend sp-forms.js to remove this behavior, or detail it in the documentation.

Thank you for the great resource. I have learned a lot from your blog/repositories.

Michael,
I came across an issue when I'm integrating many fields but most of them not being required.
I receive the following error.

Cannot convert a primitive value to the expected type 'Edm.Double'. See the inner exception for more details.

Because I have front end validation and do not care if i POST the blank values i inserted the following @ line 109 in sp-forms.js

$.each(itemObj, function(key, value){ if (value === "" || value === null){ delete itemObj[key]; } });

Hello I love this plugin! Would you please add the ability to edit the form after input? thank you.

Line 331 in sp-forms.js
var urlParams = new URLSearchParams(window.location.search);
URLSearchParams is unsupported in IE.

I have found a possible fix here.