Deprecated property could be marked as strikethrough

[oldrich-s]

Suggestion

🔍 Search Terms

deprecated strike

✅ Viability 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, new syntax sugar for JS, etc.)
• This feature would agree with the rest of TypeScript's Design Goals.

⭐ Suggestion

📃 Motivating Example

type X = {
    /** @deprecated */
    x: string
}

function fn (v: X) {}

fn({ x: 'test' })

https://www.typescriptlang.org/play?#code/C4TwDgpgBAGlC8UDeAoK6oHoBU2oAEATCMAJwgGMBDYCQqbTNDADwC4oBnYUgSwDsA5igC+KFADMArvwrBeAe35QJygBQA3DjACUycWMn81SKOygByWtwtQROoA

The x part of x: 'test' could be marked as strikethrough (x).

💻 Use Cases

People that copy-paste code will never figure out that the property has been deprecated unless they hover the property which is very unlikely. Strikethrough would immediately indicate that the copy-pasted code contains a deprecated property.

[orta]

For inside the playground? This would need to be added to monaco-typescript: https://github.com/microsoft/monaco-typescript - you're welcome to give it a shot. I'll move this issue to the TS website repo if that's what you're talking about?

[IllusionMH]

My assumption is that is not just for playground (screenshot from VS Code)

If I understood correctly: Idea is to show deprecations for properties inside of object literal that is assigned/passed to place with type that has deprecated field.

[oldrich-s]

Yes exactly.

I traced it to this._languageService.getSuggestionDiagnostics(fileName); which only returns diagnostics for a.longerName; // marked as deprecated but not for longerName: 'test'.