Reflecting properties back to attributes about hybrids

[smalluban]

I designed descriptor API to be as simple as possible. Because the set method has no access to key, it is not possible to get this value and pass it somewhere - especially do something like host.setAttribute(key, value). But, what it would be then...? A side effect, which breaks idea to use pure functions. They should not mutate host object in get, or set methods.

The architecture behind the library required out of the box patterns, which still are consistent with Web APIs. And hybrids approach reflects what is already in HTML specs - all types of <input> element treat value attribute as default and dynamic value changes only with setting value property.

I looked at the document you linked:

You never know how a user will interact with your element. They might set a property in JavaScript, and then expect to read that value using an API like getAttribute()

How we can not know how users will interact with our element ?? It should be explained in the component documentation, so this argument does not go to me.

Another example:

Create your shadow root in the constructor.

Hybrids also breaks this rule with render factory. And again this is a result of making descriptor simple - there is no construct() callback, only connect and disconnect. But, this is what the library is doing for you, so you don't have to worry about it.

One of the main goals of this library is to make things simpler - there is no "never know" - attributes are for static values - and they have to be translated from string (so there is also a cost here), properties are for dynamic values.