CodingKeyRepresentable

Published Sep 17, 2023Updated Oct 24, 2023
Contribute to Docs

The CodingKeyRepresentable protocol provides the flexibility to covert between a CodingKey type and a personalized type. This protocol enables the use of dictionaries that are not a String or Int(non-standard keys) to be encoded using organized ‘keyed’ containers instead of ‘unkeyed’ containers.

Syntax

protocol CodingKeyRepresentable

Note: CodingKeyRepresentable allows for the creation of methods to convert data into a string format that function as a key. This is particularly useful when implementing custom structs as keys.

Example

In the following example, an enum named NewSettings is declared, and it contains two options: name and instagram. This list can be used to organize data (e.g. settings for a profile). Then, a dictionary named newDict is created, and it uses NewSettings as keys to be associated with new string values.

Then a tool called JSONEncoder is used to convert this dictionary into a special format called JSON. The JSON data is turned into readable text and the output is shown in an object format.

enum NewSettings: String, Codable, CodingKeyRepresentable {
case name
case instagram
}
let newDict: [NewSettings: String] = [.name: "Jay", .instagram: "@CelticsfanJay"]
let newData = try! JSONEncoder().encode(newDict)
print(String(decoding: newData, as: UTF8.self))

This code returns the following output:

Output: {"instagram":"@CelticsfanJay","name":"Jay”}

All contributors

Looking to contribute?

Learn Swift on Codecademy