Error Handling

When GTK or GLib operations fail, GTKX throws a NativeError that wraps the underlying GError.

NativeError

When GTK operations fail, GTKX throws NativeError with the error message and code from the underlying GLib error:

import { NativeError } from "@gtkx/ffi";

try {
  await someGtkOperation();
} catch (error) {
  if (error instanceof NativeError) {
    console.log(`Error: ${error.message}`);
    console.log(`Code: ${error.code}`);
  }
}

Handling Dialog Cancellation

Dialogs throw NativeError when the user cancels. This is expected behavior:

import * as Gtk from "@gtkx/ffi/gtk";
import { NativeError } from "@gtkx/ffi";

const pickFile = async (window: Gtk.Window) => {
  try {
    return await new Gtk.FileDialog().openAsync(window);
  } catch (error) {
    if (
      error instanceof NativeError &&
      error.code === Gtk.DialogError.DISMISSED
    ) {
      return null; // User cancelled - not an error
    }
    throw error; // Actual error
  }
};

See Async Operations for more dialog examples.

Distinguishing Error Types

Use instanceof to distinguish GTKX native errors from JavaScript errors:

import { NativeError } from "@gtkx/ffi";

const handleError = (error: unknown) => {
  if (error instanceof NativeError) {
    console.log(`Native: [${error.code}] ${error.message}`);
  } else if (error instanceof Error) {
    console.log(`JS: ${error.message}`);
  }
};