Fix create node options when is undefined

[zaceno]

When using custom elements that define an is property, e.g. h('custom-foo', {is: 'button'}), then hyperapp will internally create it like this:

document.createElement('button', {is: 'custom-button'})

But whenever we don't use the is prop (as is generally the case), the call becomes

document.createElement('button', {is: undefined})

Which is not correct as far as I can tell. When there is no is, there should be no second argument at all. This PR fixes the behavior so the call becomes:

document.createElement('button', undefined)

Although browsers seem to handle the current behavior just as well, the current behavior becomes a problem with some custom element libraries that wrap the native document.createElement (don't ask me why... – I guess because of legacy cross-browser concerns?)

For example consider this example of using a-frame. It imports my modified hyperapp, but notice how it breaks when you import the latest published version of hyperapp from cdn.

[jorgebucaran]

Do you have any idea what would happen if we just createElement(..., props)? 😏

[zaceno]

Do you have any idea what would happen if we just createElement(..., props)? 😏

Not sure but I assume browsers would handle it ok, but custom-element libraries like https://github.com/dmarcos/document-register-element (which a-frame uses) would break the same way because if there is an object given as the second argument they do not expect props.is to be undefined. And they would be right, at least according to MDN:

An optional ElementCreationOptions object, containing a single property named is, whose value is the tag name of a custom element previously defined via customElements.define().

[jorgebucaran]

Sorry for the late response.

Perhaps props.is && props would be fewer bytes and work just as well. What do you think?

[zaceno]

I’ll give it a try!

[zaceno]

Good call – saves 8 bytes (minified and gzipped)! :)

[zaceno]

And works just as well!

[jorgebucaran]

I usually prettify the code (via prettier). Do you mind doing that as well?

[zaceno]

I usually prettify the code (via prettier). Do you mind doing that as well?

No problem, I can do that. Would you mind sending your prettierrc (unless you are using their defaults?) I have prettier automatically deactivated in projects that don’t have a prettierrc file in them, because I rules differ and I always end up causing some unintentional diff. But I can apply your rules and just not submit the prettierrc file.

[jorgebucaran]

The only rule I have is no semicolons. 😅

[zaceno]

🎉