Add auto-completion results to CSSStyleDeclaration.{setProperty,removeProperty}

Search Terms

setProperty

Suggestion

CSSStyleDeclaration.setProperty(propertyName, value, priority); is currently typed as setProperty(property: string, value: string | null, priority?: string | undefined): void.
There is a specific set of defined properties in CSS: https://www.w3.org/TR/CSS/#properties It would be great if this specific list of properties could be added to the definition, such that auto-completion would show the allowed values.

(The same is true for https://developer.mozilla.org/en-US/docs/Web/API/CSSStyleDeclaration/removeProperty so this feature request applies to that method as well)

For backwards compatible reasons (and to be spec-compliant), a string overload would remain. That's because the following is legal, albeit a noop:

element.style.setProperty('non-existent', 'something');

Use Cases

Improved editor experience for style APIs.

Examples

With my cursor at |, ask for the auto-completions. The expected behavior would be to show the list of accepted properties, similar to how document.createElement works.

element.style.setProperty('|

Checklist

My suggestion meets these guidelines:

• This wouldn't be a breaking change in existing TypeScript/JavaScript code
• This wouldn't change the runtime behavior of existing JavaScript code
• This could be implemented without emitting different JS based on the types of the expressions
• This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, etc.)
• This feature would agree with the rest of TypeScript's Design Goals.

Start with the CSSStyleDeclaration.setProperty and removeProperty definitions, using the existing document.createElement typing as a comparison for completion behavior. The work is done when known CSS property names appear in completion results while arbitrary strings remain accepted for backward compatibility.