JSONDecoder

JSONDecoder is a class in Swift's Foundation framework responsible for decoding JSON objects into Swift data types. It allows developers to convert data represented in JSON format into Swift's native structures such as structs, classes, and basic types like Int, String, and Bool. This process is fundamental for handling data received from APIs or stored in JSON files.

To use JSONDecoder, an instance of the class is created. This instance then provides a decode method, which takes two main arguments: the type to which the JSON should be decoded and the data containing the JSON. The data is typically obtained from a network request or read from a file. The decode method returns an instance of the specified Swift type.

The decoding process can encounter errors, such as malformed JSON, missing keys, or type mismatches between the JSON and the Swift model. JSONDecoder is designed to throw errors in such situations, allowing developers to implement error handling using do-catch blocks. Customization options are available, such as setting a date decoding strategy or a key decoding strategy, which can alter how JSON keys are mapped to Swift property names. This flexibility makes JSONDecoder a powerful tool for managing external data in Swift applications.