Deemphasize old JSX transform

[eps1lon]

The old JSX transform requires a React import so you get a "This JSX tag requires 'React' to be in scope, but it could not be found.ts(2874)" for files without a tsconfig in VSCode by default.

However, the default nowadays is the new, automatic JSX transform in React which doesn't need a React import so VSCode should default to that.

Related:

• Update compilerOptions.jsx to reflect latest preferences TypeScript-Website#2994
• Deemphasize old JSX transform TypeScript#61586

[RyanCavanaugh]

What do you think about preserve instead? It's the most agnostic/forgiving, right?

[eps1lon]

The problem with preserve is that it would not pick up any JSX types in that case even if you have @types/react installed. And I guess if you don't have any types installed, it would also not try to download @types/react with automatic type aquisition?

I can see why it makes more sense to be agnostic but I don't think preserve is the best practical choice as a default.

[jcalfee]

Possibly related: I'm using solidjs and mostly it is usually fine without this error. But after moving files around, the editor occasionally gets hung up on This JSX tag requires 'React' to be in scope, but it could not be found. making it think everything, even <div(s)..>, are an error (v1.98.2). I basically have to restart the editor to get this error to clear up (only affects certain files; likely the one I'm working with).

[eps1lon]

That seems unrelated to this change considering that error is the one you get with the previous defaults. The new default would not trigger this error since React doesn't need to be in scope with react-jsx