Allow ability to do an in-place override (_not_ extend) of interface properties

[ffxsam]

Search Terms

override interface
override interface replace

Suggestion

It would be nice to be able to override (not extend) third party libraries' interfaces to change the types/signatures of the interface properties.

Use Cases

Sometimes they make mistakes or define interfaces in ways that force me to constantly use as to typecast. I'd rather short-circuit it in one place so it works across my project.

Examples

Reference: https://stackoverflow.com/questions/51562792/how-to-override-a-typescript-interface-without-extending

Checklist

My suggestion meets these guidelines:
(Honestly I'm in no position to make these judgment calls, as I don't know the inner workings of this library - why ask these quesitons?)

• 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 (not sure what this means)
• This isn't a runtime feature (e.g. new expression-level syntax) (???)

[aleclarson]

I think a core problem here is: in the case of multiple overrides of the same property, how would the type-checker decide which override takes precedence?