Recognize jsxImportSource namespaces in checked JavaScript

[Copilot]

Checked .js files using jsxImportSource failed to resolve the runtime module’s JSX namespace, while equivalent .tsx files worked.

// checkJs: true, jsxImportSource: "preact"
<div />;

• Root cause

  • JSX runtime imports were synthesized for JSX/TSX script kinds, excluding .js files.

• Change

  • Include JavaScript source files when synthesizing JSX runtime imports.
  • Add compiler coverage verifying JSX.IntrinsicElements resolves from preact/jsx-runtime.

[jakebailey]

Ah yes, the classic "JS is actually JSX" thing

[Copilot]

Pull request overview

Extends JSX runtime namespace resolution to checked JavaScript files.

Changes:

• Synthesizes JSX runtime imports for .js and .jsx files.
• Adds compiler coverage with type and symbol baselines.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
internal/compiler/fileloader.go	Includes JavaScript files in JSX runtime import resolution.
testdata/tests/cases/compiler/jsxImportSourceCheckJs.ts	Adds the regression test.
testdata/baselines/reference/compiler/jsxImportSourceCheckJs.types	Verifies resolved JSX element types.
testdata/baselines/reference/compiler/jsxImportSourceCheckJs.symbols	Verifies intrinsic element symbol resolution.

[caseywebdev]

Awesome, thanks 🙏🏻