We continue where we left off last time and dive into writing our first lines of code. The core of any app is the app logic, and a big part of the app logic is in the data models. What kind of data we will work with internally? How will that data be stored in memory? In this video, we will write our data models, make them Codable (and we learn what that means), and create a global public function that will read and decode our three JSON files we prepared last time, in order to populate our newly created data models with real data.
Outline
writing a struct
let versus var
what is the Codable protocol and how to make a custom structure conform to Codable
what is an optional type
what is a static function
how to guard against particular conditions
how to deal with functions that throw (an error)
the do-try-catch code syntax mechanism
provided .debugDescription computed property on optional types
data types/structures available in the Foundation framework:
URL
Data
JSONDecoder
Error
how to decode JSON data into a custom structure
how to locate a resource file in the app bundle with Bundle.main.url(forResource:withExtension:)
how to read the contents of an URL into a Data object with the initializer Data(contentsOf:)
how to decode a Data object into a custom structure with JSONDecoder(_,from:)