fix(viewer): serve static js with script mime type

viewer/handler_test.go

@@ -82,3 +82,22 @@ func TestStandaloneHandlerRootShowsUploadForm(t *testing.T) {
 		t.Fatalf("expected standalone handler root to include upload form")
 	}
 }
+
+func TestStaticJSUsesScriptContentType(t *testing.T) {
+	handler := NewHandler(HandlerOptions{Title: "Reanimator Chart"})
+
+	req := httptest.NewRequest(http.MethodGet, "/static/view.js", nil)
+	rec := httptest.NewRecorder()
+	handler.ServeHTTP(rec, req)
+
+	if rec.Code != http.StatusOK {
+		t.Fatalf("status = %d, want %d", rec.Code, http.StatusOK)
+	}
+	contentType := rec.Header().Get("Content-Type")
+	if !strings.Contains(contentType, "javascript") {
+		t.Fatalf("Content-Type = %q, want javascript MIME type", contentType)
+	}
+	if !strings.Contains(rec.Body.String(), "DOMContentLoaded") {
+		t.Fatalf("expected static JS asset body to be served")
+	}
+}

web/embed.go

@@ -4,6 +4,7 @@ import (
 	"embed"
 	"html/template"
 	"io/fs"
+	"mime"
 	"net/http"
 	"strings"
 )
@@ -19,6 +20,12 @@ var pageTemplate = template.Must(template.New("view.html").Funcs(template.FuncMa
 
 var uploadTemplate = template.Must(template.New("upload.html").ParseFS(content, "templates/upload.html"))
 
+func init() {
+	if err := mime.AddExtensionType(".js", "text/javascript; charset=utf-8"); err != nil {
+		panic(err)
+	}
+}
+
 func Render(data any) ([]byte, error) {
 	var out strings.Builder
 	if err := pageTemplate.ExecuteTemplate(&out, "view.html", data); err != nil {