Last week I created a date formatter to display relative dates. Basically, whether I get a date I need to create a string with the relative date: today, yesterday, etc or if the date can't be relative,  I must to display another custom formatter date, for instance Jan 18, 2018 at 5:29 PM. Besides, It needs to be localized, for example in french would be aujourd’huihier and avant-hier.

Set, An unordered collection of unique elements, is one of the most important collections types in Swift (arraydictionary and set)

You use set instead of an array when:
1. You aren't concerned about the order of the elements (Order does not matter)
2. You need to ensure that every element only appears once (no duplicated values)
3. You need to test efficiently for membership

I'm creating a minimal API for Slack, it basically sends messages to users, private channels and public channels. In every request I need to add the same parameter, a valid token. Without this token my requests will fail.

In this case I need a valid token, but in other scenarios you need to create request with same headers, parameters

A few weeks ago, I learned how to retrieve data from Instagram's private API. How? I was diving into the app store, searching apps that were using the Instagram public API, apparently. It was curious that some of them directly didn't use a token to retrieve information: basic user profile, media, relationships... they were pointing to