Extend Watchfile options to allow for watching some files with higher priority.

Suggestion

🔍 Search Terms

• Watch specific file
• Restart part of TS server
• send an event to ts server

✅ 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

Provide the ability to watch some files closely for changes to make VSCode intellisense work faster.

📃 Motivating Example

I generate a some typescript code from an openapi specification, and the typescript language server fails to update the types in a timely manner.

💻 Use Cases

I want to use this to create a much much faster feedback loop between the API client type and the API sever contract.
Here is a possible flow:

1. I make a change to my sever code (i.e. django app)
2. Which generates a change to the schema (graphql, openapi, protobuff)
3. Which generates some new typescript code
4. Which is instantly available for my IDE, as if the server code was written in typescript in the same project.

All of this hopefully happens as fast as possible (maybe 250ms is reasonable)

Imagine TRPC, but make it for language-agnostic backends.

The issue names TypeScript's watchfile options, the TypeScript language server, and VSCode IntelliSense, but no source files or tests. Start by locating the language-server watch handling and its existing watch options; the work is done when a specified set of files can be watched with higher priority and generated TypeScript updates reach IntelliSense promptly.