ElementTagNameMap should extend HTMLElementTagNameMap

[justinfagnani]

TypeScript Version: 2.2.1

Code

Along with #14782, this would let custom element definitions be able to augment only one tag name map:

export class FooElement extends HTMLElement {}
customElements.define('foo', FooElement);

declare global {
  interface HTMLElementTagNameMap {
    "foo": FooElement,
  }
}

And with #14783 ElementTagNameMap could extend both HTMLElementTagNameMap and the proposed SVGElementTagNameMap.

[mhegazy]

PRs welcomed. You can find more information about contributing lib.d.ts fixes at https://github.com/Microsoft/TypeScript/blob/master/CONTRIBUTING.md#contributing-libdts-fixes.

[justinfagnani]

Looks like this was fixed in microsoft/TypeScript-DOM-lib-generator@072c548