WebGL IDL generated types should use ArrayLike<*> for sequence<*>

[jessevdk]

TypeScript Version: 3.2.0-dev.201xxxxx

Search Terms: WebGL, idl, float32list

Code

const ctx: WebGLRenderingContext = null;
const value: ArrayLike<number> = [0, 1, 2];

ctx.uniform3fv(0, value);

Expected behavior: Compiles without errors (used to work in 3.0)

Actual behavior: Compiles with error since ArrayLike<number> isn't assignable to Float32Array nor number[]

Playground Link: http://www.typescriptlang.org/play/#src=const%20ctx%3A%20WebGLRenderingContext%20%3D%20null%3B%0D%0Aconst%20value%3A%20ArrayLike%3Cnumber%3E%20%3D%20%5B0%2C%201%2C%202%5D%3B%0D%0A%0D%0Actx.uniform3fv(0%2C%20value)%3B

Related Issues: Wrong WebGLRenderingContext interface definition for pixelStorei #27542

[weswigham]

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.

[saschanaz]

As I wrote in microsoft/TypeScript-DOM-lib-generator#592, Web IDL sequence requires iterator support but ArrayLike does not.

[weswigham]

Iterable aughta be correct then, right?

[saschanaz]

Yes, but unfortunately we cannot use Iterable because of es3/5 compatibility. (#23610)

[saschanaz]

Maybe we still can add overloads via dom.es6.d.ts in this case.

[weswigham]

Aye, that's what I was thinking. The es6 Dom lib seems like just the place for an overload like this.

[saschanaz]

Oh, I just remembered that I opened an issue exactly for this purpose. microsoft/TypeScript-DOM-lib-generator#443

I can start working on this if the team agrees.

[Istar-Eldritch]

That makes more sense @saschanaz.
Does that make microsoft/TypeScript-DOM-lib-generator#592 obsolete in favour the general sequence override approach? Or should we keep the dom.generated.d.ts with number[]?

Also, does this change the scope to a more general approach? Should all number sequences in dom.generated.d.ts be overrided to number[]?

[saschanaz]

We should keep existing number[] so that ES5 can keep passing arrays.

Should all number sequences in dom.generated.d.ts be overrided to number[]?

I'm not sure I understand. sequence<number> is already being translated into number[].

[Istar-Eldritch]

I'm not familiar with the codebase so I'm probably missing something.

The baselines defines only Float32Array which doesn't accept number[]. Reference

If the translation to number[] is done already, where is it? Otherwise, It's your intention to do translation to number[] as part of microsoft/TypeScript-DOM-lib-generator#443?

[saschanaz]

But L15924 doesn't contains Float32Array? If you mean Float32List, it's a union type of Float32Array and number[].