1. @DomName('ConsoleBase.assert')
  2. @DocsEditable()
  3. @Experimental()
void assertCondition(bool condition, Object arg)

Source 

@DomName('ConsoleBase.assert')
@DocsEditable()
@Experimental() // untriaged
void assertCondition(bool condition, Object arg) =>
    _blink.BlinkConsoleBase.instance.assert_Callback_2_(this, condition, arg);