improvements for non-experimental decorator types

🔍 Search Terms

github typescript decorator value type

✅ Viability Checklist

• 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 isn't a request to add a new utility type: https://github.com/microsoft/TypeScript/wiki/No-New-Utility-Types
• This feature would agree with the rest of our Design Goals: https://github.com/Microsoft/TypeScript/wiki/TypeScript-Design-Goals

⭐ Suggestion

This is a request to add a new utility type because TypeScript added one for decorator contexts but not for values

The DecoratorContext type is nice for catching all context types:

function decorator(value: unknown, context: DecoratorContext) { // optionally use a more specific type.
  // ...
}

But for value, there is not a good catch-all type.

📃 Motivating Example

If we have a context catch all type, why not also have a value catch all type, f.e. something like :

export type DecoratedValue = Constructor | Function | ClassAccessorDecoratorTarget<object, unknown> | undefined

💻 Use Cases

1. What do you want to use this for? decorators whose code handles any value type
2. What shortcomings exist with current approaches? we have to make the catchall for value ourselves, but we don't have to do that for context
3. What workarounds are you using in the meantime? I make my own catchall (not that big a deal, but neither would making DecoratorContext myself be

No file or test is named. Start by locating the existing DecoratorContext declaration and the decorator type definitions it covers, then compare the proposed DecoratedValue members with the current type system. Done means an agreed catch-all value type is added without changing emitted JavaScript or existing behavior.