[Custom]: Add the possibility to extend the custom element (bugzilla: 26583)

[hayatoito]

Title: [Custom]: Add the possibility to extend the custom element (bugzilla: 26583)

Migrated from: https://www.w3.org/Bugs/Public/show_bug.cgi?id=26583

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comment: 0
comment_url: https://www.w3.org/Bugs/Public/show_bug.cgi?id=26583#c0
** wrote on 2014-08-14 08:41:54 +0000.

Example:

var Modal = document.registerElement('x-modal', {
prototype: Object.create(HTMLElement, {/* modal generic prototype /})
})
var WebcamModal = document.registerElement('x-webcam', {
extends: 'x-modal',
prototype: Object.create(Modal, {
/ webcam modal specific prototype */
show: {
value: function() {
Modal.prototype.show.call(this)
// run webcam
}
}
})
})

And will be cool if will be possible to have a non-dashed name of extend name (is="webcam" instead is="x-webcam").

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comment: 1
comment_url: https://www.w3.org/Bugs/Public/show_bug.cgi?id=26583#c1
Tab Atkins Jr. wrote on 2014-08-14 14:57:20 +0000.

There is no "non-dashed version" of a name, because there's no common structure to the name that we can safely ignore. The sole requirements it that a dash appears somewhere in the name, so it can occur between or around significant or insignificant parts, and there's no way to tell automatically what parts are insignificant.

[annevk]

Is the only problem here that is="" is also required to contain a hyphen?

[annevk]

Closing this. @domenic, please reopen if you disagree.

[domenic]

In general I do think it's a bit weird that type extensions rely on a lot of the same constraints and infrastructure as custom tags, when there's no real reason to do so. E.g. maybe in my ideal world you'd have customElements.define("custom-tag", CustomTag) and customElements.defineExtension("button", "plastic", PlasticButton), instead of lumping them both together with customElements.define("custom-name", CustomTag, { extends: "button" }). But I'm not sure it's worth the churn. Especially since there's a weak argument that the hyphen encourages namespacing, anyway.