Encodable and Decodable are the powerful features in swift standard library to handle data encoding and decoding tasks easily. Many types in swift standard library and Foundation framework such as Date, URL are Codable out of the box which makes Encodable and Decodable compelling for data serialization/deserialization.
What is Encodable and Decodable?
Codable means they can be decoded from and encoded into another representation. Decodable means it can be decoded, but not encoded. And encodable is the opposite of that. Follow this answer to receive notifications.
What does Encodable mean?
(ɪnˈkəʊdəbəl) adj. able to be encoded. Want to thank TFD for its existence?
What is decode in Swift?
The three-step process to decode JSON data in Swift Perform a network request to fetch the data. Feed the data you receive to a JSONDecoder instance. Map the JSON data to your model types by making them conform to the Decodable protocol.
What is Decodable Swiftui?
A type that can decode itself from an external representation.
What are Encodable words?
(ɪnˈkəʊdəbəl ) adjective. able to be encoded.
What does the term Decodable mean?
Decodable definition Able to be read using a certain set of reading knowledge. Decodable books are sold in packs, with more letter combinations appearing in each successive book. adjective. (information theory) Of a code, having a non-singular extension; being a lossless encoding. adjective.
What is serialization in Swift?
2019. Serialization is a process of converting your instances to another representation, like a string or a stream of bytes. The reverse process of turning the data into an instance is called decoding, or deserialization.
What is encoding in Swift?
A common task for iOS apps is to save data and send it over the network. But before you can do that, you need to convert the data to a suitable format through a process called encoding or serialization. You'll also need to convert the saved data sent over the network to a suitable format before using it in your app.
What are Codingkeys in Swift?
A type that can be used as a key for encoding and decoding.
How do you use Decodable?
Select the decodable reader that contains the letter sound knowledge your students know and need to practise. For example, a student needs to practice the long vowel sounds so a reader containing /ai/ words may be selected. Remember that this letter sound knowledge must be explicitly taught prior to reading.
What is considered Decodable text?
Decodable text is a type of text used in beginning reading instruction. Decodable texts are carefully sequenced to progressively incorporate words that are consistent with the letter–sound relationships that have been taught to the new reader.
What is JSON decoder in Swift?
Handling JSON data in Swift With the Foundation classes JSONDecoder and JSONEncoder, JSON data can be parsed in Swift and Swift values can be converted to JSON. It is recommended to define suitable data types as struct, which correspond 1:1 to the structure from the JSON.
NSCoding
It is a protocol that a class must adopt the NSCoding protocol and implement its required methods in order for us to decode and encode JSON data.
Encode and Decode Automatically
The simplest way to make a type codable is to declare its properties using types that are already Codable.
CodingKeys
then we conform the protocol CodingKeys to rename the key/variable as we want as below. CodingKey is A type that can be used as a key for encoding and decoding.
JSON
JSON is an open standard file format, and data interchange format, that uses human-readable text to store and transmit data objects consisting of attribute value pairs and array data types.
Encodable and Decodable protocols
The Encodable protocol is used by types that can be encoded to another representation. It declares a single method:
What is Codable?
Codable is a protocol that a type can conform to, to declare that it can be encoded and decoded. It’s basically an alias for the Encodable and Decodable protocols.
Automatic encoding and decoding
There are many types in Swift that are codable out of the box: Int, String, Date, Array and many other types from the Standard Library and the Foundation framework. If you want your type to be codable, the simplest way to do it is by conforming to Codable and making sure all its stored properties are also codable.
Encoding and decoding custom types
There are several representations you can encode to or decode from, such as XML or a Property List. In this section, you’ll learn how to encode to and decode from JSON, by using Swift’s JSONEncoder and JSONDecoder classes.
Renaming properties with CodingKeys
It turns out that the gifts department API requires that the employee ID appear as employeeId instead of id. Luckily, Swift provides a solution to this kind of problem.
Manual encoding and decoding
You try to send the data over to the gifts department, and again the data gets rejected. This time they claim that the information of the gift you want to send to the employee should not be inside a nested type, but rather as a property called gift. So the JSON should actually look like this:
Writing tests for the Encoder and Decoder
If at any time you change your encoder and forget to update the decoder (or vice versa) you might get nasty errors at runtime. In order to avoid this situation, it’s recommended that you write unit tests to make sure you never break the encoding or decoding logic.
