This might be just a few levels of people talking past each other, but just in case: Yes, the full "standard libarary" you can expect to be present on any give

This might be just a few levels of people talking past each other, but just in case: Yes, the full "standard libarary" you can expect to be present on any given JS VM may vary, but there's no plausible reason that e.g. at() should not work on almost any conceivable platform.