js: Support JSX and JSXImportSourceOptions

Fixes #12118

resources/resource_transformers/js/options.go

@@ -86,6 +86,14 @@ type Options struct {
 	// What to use instead of React.Fragment.
 	JSXFragment string
 
+	// What to do about JSX syntax.
+	// See https://esbuild.github.io/api/#jsx
+	JSX string
+
+	// Which library to use to automatically import JSX helper functions from. Only works if JSX is set to automatic.
+	// See https://esbuild.github.io/api/#jsx-import-source
+	JSXImportSource string
+
 	// There is/was a bug in WebKit with severe performance issue with the tracking
 	// of TDZ checks in JavaScriptCore.
 	//
@@ -375,6 +383,19 @@ func toBuildOptions(opts Options) (buildOptions api.BuildOptions, err error) {
 		return
 	}
 
+	var jsx api.JSX
+	switch opts.JSX {
+	case "", "transform":
+		jsx = api.JSXTransform
+	case "preserve":
+		jsx = api.JSXPreserve
+	case "automatic":
+		jsx = api.JSXAutomatic
+	default:
+		err = fmt.Errorf("unsupported jsx type: %q", opts.JSX)
+		return
+	}
+
 	var defines map[string]string
 	if opts.Defines != nil {
 		defines = maps.ToStringMapString(opts.Defines)
@@ -416,6 +437,9 @@ func toBuildOptions(opts Options) (buildOptions api.BuildOptions, err error) {
 		JSXFactory:  opts.JSXFactory,
 		JSXFragment: opts.JSXFragment,
 
+		JSX:             jsx,
+		JSXImportSource: opts.JSXImportSource,
+
 		Tsconfig: opts.tsConfig,
 
 		// Note: We're not passing Sourcefile to ESBuild.

resources/resource_transformers/js/options_test.go

@@ -135,6 +135,20 @@ func TestToBuildOptions(t *testing.T) {
 			Loader: api.LoaderJS,
 		},
 	})
+
+	opts, err = toBuildOptions(Options{mediaType: media.Builtin.JavascriptType,
+		JSX: "automatic", JSXImportSource: "preact"})
+	c.Assert(err, qt.IsNil)
+	c.Assert(opts, qt.DeepEquals, api.BuildOptions{
+		Bundle: true,
+		Target: api.ESNext,
+		Format: api.FormatIIFE,
+		Stdin: &api.StdinOptions{
+			Loader: api.LoaderJS,
+		},
+		JSX:             api.JSXAutomatic,
+		JSXImportSource: "preact",
+	})
 }
 
 func TestResolveComponentInAssets(t *testing.T) {