Select .options attribute should be an HTMLOptionsCollection

[jasongrout]

TypeScript Version:

1.9.0-dev (commit be6c34f)

Description

In https://github.com/Microsoft/TypeScript/blob/be6c34f1c79ec998c56ae127e572ffa9d7794b51/lib/lib.dom.d.ts#L6797, .options should be an HTMLOptionsCollection, which would have typed add/remove methods. We have an HTMLOptionsCollection defined at https://github.com/Microsoft/TypeScript/blob/be6c34f1c79ec998c56ae127e572ffa9d7794b51/lib/lib.dom.d.ts#L6633, but I think it should probably inherit from HTMLCollectionOf<HTMLOptionElement> (possibly unioned with an optgroup type too) for the typed index accessors, etc.

Also, HTMLOptionsCollection shouldn't have a selectedIndex: number; attribute according to the spec at https://www.w3.org/TR/2011/WD-html5-20110525/common-dom-interfaces.html#htmloptionscollection-0

Code

// A self-contained demonstration of the problem follows...
document.createElement('select').options

cf. #8220

[mhegazy]

I am not sure i understand why this changed but, 9a55fac should show the fixed definition.

[mhegazy]

should be in typescript@next later tonight.

[mhegazy]

Also, HTMLOptionsCollection shouldn't have a selectedIndex: number; attribute according to the spec at https://www.w3.org/TR/2011/WD-html5-20110525/common-dom-interfaces.html#htmloptionscollection-0

I am a bit confused:

from https://www.w3.org/TR/2011/WD-html5-20110525/common-dom-interfaces.html#htmloptionscollection-0

interface HTMLOptionsCollection : HTMLCollection {
  // inherits item()
  attribute unsigned long length; // overrides inherited length
  caller getter object namedItem(in DOMString name); // overrides inherited namedItem()
  void add(in HTMLElement element, in optional HTMLElement before);
  void add(in HTMLElement element, in long before);
  void remove(in long index);
  attribute long selectedIndex;
};

from lib.d.ts:

interface HTMLOptionsCollection extends HTMLCollectionOf<HTMLOptionElement> {
    length: number;
    selectedIndex: number;
    add(element: HTMLOptionElement | HTMLOptGroupElement, before?: HTMLElement | number): void;
    remove(index: number): void;
}

and both has selectedIndex.

[jasongrout]

and both has selectedIndex.

You're right! My mistake.

Should HTMLOptionsCollection extend HTMLCollectionOf<HTMLOptionElement | HTMLOptGroupElement> to account for optgroup elements? (I'm not sure if .options will list option group elements alongside option elements).

[jasongrout]

Thanks for the fast response on this!

[mhegazy]

Can you explain why you think it should be a union?

[aluanhaddad]

I suppose it is because both types are valid elements in the collection, but neither is declared as a subtype of the other. Actually, the instance side of both types is identical, but this is not clear from reading their definitions.

var x: HTMLOptGroupElement;
var y: HTMLOptionElement = x;
x = y;

is perfectly valid, but they are not explicitly related. A union would be clearer, but it would not affect typing.