add stack trace for syntax errors

src/code_runner.js

@@ -31,6 +31,12 @@ export class CodeRunner {
             const module = await import(`data:text/javascript;charset=utf-8,${encodedText}`);
             this.evalScope = Object.assign(this.evalScope, module);
         } catch (error) {
+            Error.captureStackTrace(error, this.run);
+
+            if (!error.stack || error instanceof SyntaxError) {
+                error.stack = `${error.fileName}:${error.lineNumber}:${error.columnNumber}`;
+            }
+
             this.console.error(error);
         }
     }