Allow prepending --watch with --clean in CLI --build mode?

Suggestion

🔍 Search Terms

tsc watch build clean

✅ 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

It would be nice to be able to run tsc --build --clean --watch and have the --clean operation run before the --watch operation. Today we have to run these commands separately.

📃 Motivating Example

For developing TypeScript itself, I'll frequently run tsc -b src/tsc -w to get built/local/tsc.js created. But other commands such as gulp runtests seem to clobber over the inputs and/or outputs so I've found I need to first tsc -b src/tsc --clean when running them.

💻 Use Cases

In general, this would be a nice little shortcut for folks who want to first clean, then watch.

Start at the tsc CLI handling for --build, --clean, and --watch, and trace how these options are currently combined or rejected. Done means tsc --build --clean --watch cleans first and then enters watch mode, while existing command behavior remains unchanged.