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DOM lib: CSS namespace breaks CSS Typed OM #38554
Description
TypeScript Version: 3.9.2
Search Terms: CSS level 1 types lib dom
PR #37616 changed the definition of CSS from an interface with a global var to a namespace.
// Before:
interface CSS {
escape(value: string): string;
supports(property: string, value?: string): boolean;
}
declare var CSS: CSS;
// After:
declare namespace CSS {
function escape(ident: string): string;
function supports(property: string, value: string): boolean;
function supports(conditionText: string): boolean;
}In isolation, this is all fine.
But it breaks additional definitions for newer standards.
I reference @types/w3c-css-typed-object-model-level-1 for typed CSS OM, which uses the same interface + global var approach as TS 3.8.
Before it was working fine.
After 3.9, code such as CSS.px(42) now errors with TS2339 'px' does not exist on type 'typeof CSS'
Activity
AviVahl commentedon May 13, 2020
The actual change was in another repository: microsoft/TypeScript-DOM-lib-generator#716
TypeScript syncs its
.d.tsfiles with it.It appears that by moving CSSOM types to be a built-in part of TypeScript, the following spec was missed: https://www.w3.org/TR/css-typed-om-1/
It contains the IDLs for functions like
CSS.px, previously available via@types/w3c-css-typed-object-model-level-1.Kagami Sascha Rosylight (@saschanaz) Nathan Shively-Sanders (@sandersn)
I tried adding the following source to
idlSources.json:but the auto-generated namespace contained
function in(...)(forCSS.in(123)), which is illegal, asinis a reserved word. Trying to useremovedTypes.jsonto override the namespace was a bust, as theprunefunction assumes string-based array filtering (namespace has named objects).Also, the URL for the Speech API is outdated and causes an un-handled promise rejection (in IDL fetching script). The new URL is: https://wicg.github.io/speech-api/
saschanaz commentedon May 14, 2020
Typed OM so far hasn't get enough stable implementations, and thus doesn't meet the standard to be included in the lib.
That said, the namespace compatibility is a thing. I hope TS could merge namespace and interface seamlessly.
AviVahl commentedon May 14, 2020
I understand. Makes sense.
The issue is therefore about the assumption regarding
@types/w3c-css-typed-object-model-level-1no longer being needed. That assumption has proven to be incorrect, as the new built-in types don't include everything that was defined there.A possible solution is to "revive"
@types/w3c-css-typed-object-model-level-1(or whatever shorter name) with what's missing, probably withnamespaceusage this time around.saschanaz commentedon May 23, 2020
True, DefinitelyTyped/DefinitelyTyped#43361 should be reverted.
sandersn commentedon May 26, 2020
After the revert, a lot of the package will still need to be removed, right? Or, wait, if it only includes CSS Typed OM types, then a simple revert should be good enough.
saschanaz commentedon May 26, 2020
A revert should use
namespace CSS, otherwise a simple revert looks fine.sandersn commentedon May 26, 2020
PR is up at DefinitelyTyped/DefinitelyTyped#45076
dpraul commentedon Jun 25, 2020
I encountered this updating our application from Angular 9 to 10, since 10 brings in TS 1.9. Our app scopes
CSSto a class so it can be overridden in tests.For any relative TS newbies like me who stumble on this, I was able to workaround by changing:
to: