Added methods to auto trigger base(). Removed unused event methods. Modified Comments
Added new methods for setting new base currency and update the exchange rates previously loaded. Tested to set an original base currency, and then update it, to test that the DOM updated properly. Due to decimal lack of precision, the rate of the new base currency in the currencies array was manually set to 1. Delete unused exist method, leaving for future updates the encapsulation of common behaviour of methods (for and if === desc). Updated ON method for correctly tkae parameters