missing whole Custom Elements API

[scalway]

missing classes in

org.scalajs.dom.raw:

• ShadowRoot
• HTMLSlotElement
• HTMLTemplateElement

in Element:

/** Creates a shadow root for element and returns it. */
def attachShadow(init:js.Any):ShadowRoot

• CustomElementRegistry

in Window:

def customElements:CustomElementRegistry

new interface that HTMLElement should extends

interface Slotable {
    readonly assignedSlot: HTMLSlotElement | null;
}

caniuse of ShadowDom

Should I send PR or we are not interested this API until it is covered by all browsers?

[sjrd]

In general, we accept PRs for APIs that are specified in the DOM standard, unless there is some evidence that it won't be implemented in all browsers. If it's not yet implemented in all browsers, but it's standardized, that's fine.

[mseddon]

That would usually live in the org.scalajs.dom.experimental sub package. The point being anything imported from org.scalajs.dom should always work across all supported browsers to minimise confusion, but partially adopted APIs are always encouraged in the library there. The general approach is to have an import that enriches the relevant type via implicits.

[scalway]

I leave it 4 now. Scalajs 0.6 does not compile ES2015 with Google Closure Compiler. It means we are not ready to write WebComponents using 0.6 tree yet. It could be useful for scalajs 1.0 (where fullOpt'll produce minified version) but not there yet. I have some code of it in my internal project but it needs to be polished

I'll continue my experiments with WebComponents when 1.0 version will be in RC state. Hopefully browser support'll increase up to then.

[mseddon]

@sjrd I have been on a rather long hiatus from Scala so my information is embarrassingly out of date, sorry! :)

The issue with providing WebComponents 1.0 here is that it will require ES6 class syntax to even function, since it requires extending HTMLComponent using modern class syntax. Does Scala.js produce ES6 or above out of the box now, and if we optionally provide ES5 fallbacks, how should we expose it without breaking ECMA5 users? (I suspect it will probably just 'not work' without choking Scala.js builds, but it would be nice to alert the user that it's futile trying at compile time). I am fairly sure we have moved passed 0.6 though...

[sjrd]

Scala.js 0.6.x has provided an option to emit ECMAScript 2015 (ES 6) for years:

scalaJSLinkerConfig ~= { _.withESFeatures(_.withUseECMAScript2015(true)) }

Scala.js 1.0.0-M7 and above emit ECMAScript 2015 by default, and the same option with false can be used to force it to emit ES 5.1.

[armanbilge]

@scalway at a quick glance it seems some of these APIs are more widely supported now, if you're still up for it we can consider a PR for the experimental package.

[armanbilge]

Marking as duplicate of #191.