Strikeout CompletionItems (and Symbols?) that are deprecated

[rcjsuen]

Ctrl+Space is nice and all but when you are new to a library you just see a list of functions and you won't realize that some of them are deprecated. Would it be possible to add a strikeout line via the line-through text-decoration or some kind of icon overlay to indicate that something is deprecated?

[vscodebot]

(Experimental duplicate detection)
Thanks for submitting this issue. Please also check if it is already covered by an existing one, like:

• Add extension deprecation and redirection (#4772)

[octref]

@jrieken I'm interested in this too, for deprecated html/css properties.

[ivanvoznyakovsky]

it'd also be great to strikeout deprecated props/methods in the editor itself like webstorm does it. ie

[KamasamaK]

@ivanvoznyakovsky The only way to currently set whether the property or method is deprecated would be to use invalid.deprecated in the TM syntax. I have proposed the capability of doing this through the API in #56694

[jcrben]

Raised a couple times previously:

• Feature request: highlight deprecated functions (JS/TS) #31159
• @deprecated support in TypeScript #10316 - recommends using extension with textDecoration API @deprecated support in TypeScript #10316 (comment)

At least we currently should see when using trying to use an @deprecated function (#26541)

[KamasamaK]

@jcrben Those are issues for language support. This issue is more general, and I think this is an issue to support the deprecated property on the completion and symbol items in the LSP spec with a visual change. Perhaps also to add those properties to the native API.

When this is done, I would expect more language support would follow. It's possible that some language servers already do set that property but you don't know since VS Code ignores it.

Specifically on those issues you posted, I don't agree with the notion that it should be done in a separate extension or that it should use the decorations API. Deprecation is a standard practice in software development, and in the case of JavaScript/TypeScript there is JSDoc to determine this, which is already being parsed and used for other doc tags.