How does the irony in "Araby" heighten the moment of epiphany within the story?
There are many different types of irony, but, in general terms, something is ironic when something very different than what was expected happens. Often, irony is used for comedic purposes but, in the case of James Joyce's "Araby," irony has more to do with bitterness and melancholy than with humor.
In "Araby," a little boy has an intense crush on Mangan's sister, one of the girls living in his neighborhood. Mangan's sister asks the narrator to buy her a gift at the bazaar, and the boy gleefully imagines this to be his chance to prove his love through some grand, romantic gesture. However, when the boy finally arrives at the bazaar, he finds it to be a far cry from the exotic adventure he imagined, as it is dark, largely empty, and uninviting. The story ends with an epiphany, as the narrator realizes his dreams of love have been foolish childhood fantasies.
The irony here is that, instead of being an exciting display of foreign treasures, the bazaar is rather disappointing. Moreover, despite his obsessive desire to find a gift for Mangan's sister, the narrator does not ultimately buy her anything. The ironic end emphasizes the narrator's epiphany and displays the foolishness of his childhood fantasies, revealing them to be at odds with the harsh reality of the adult world. All in all, irony is an important element in "Araby," as its presence underlines the bitterness of the narrator's epiphany.