The reason is because you only set up your array to hold 3 items. When you typed a 3 instead of a 2 you were trying to access item number 4 (0 to 3, remember). But you haven't defined a fourth item. Even though you haven't got a fourth item, Javascript doesn't throw you up an error, it doesn't refuse to work.
Refactoring. Refactoring is the process of clarifying and simplifying the design of existing code, without changing its behavior.Agile teams are maintaining and extending their code a lot from iteration to iteration, and without continuous refactoring, this is hard to do. This is because un-refactored code tends to rot.efactoring is the process of clarifying and simplifying the design of existing code, without changing its behavior. Agile teams are maintaining and extending their code a lot from iteration to iteration, and without continuous refactoring, this is hard to do.
reference noun (IN A PIECE OF WRITING) B2 [ C ] a writer or a book, article, etc. that is mentioned in a piece of writing, showing you where particular information was found. âº [ C ] abbreviation ref in a business letter, a number that tells you who to speak to or where to look for more information: