Comment by sporritt
It is true that web components can have properties and accessors like any object. But what you cant do is pass anything other than a string to a web component's attributes in the markup. I wrote a short article about this when I was investigating web components with JsPlumb a while ago:
https://jsplumbtoolkit.com/blog/2024/07/18/wrapping-data-in-...
TL;DR I ended up creating a context object and a BaseComponent that can access the context. Subclasses of the base component prefix their attributes with a colon to instruct the code to look in the context:
<date-label :value="now"></date-label>
I think you might be missing out on the standard Time element in HTML5. In use, you set its datetime attribute to a machine-readable format and set its body to the user-readable format.
Also, I tend to think of HTML not as my application view, but as a document that represents a serialization of your view. The actual, live view itself is the DOM. Once that document is parsed and rendered, the HTML source from whence it came doesn't matter anymore. Stringly attributes should no longer be a concern.
Though, admittedly, the HTMLTimeElement's dateTime property is still a string value. I imagine that is more of a legacy issue. The Date class in JavaScript is a mess as well.