Save custom objects into UserDefaults

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In this post, I will discuss how to save a custom object in UserDefaults. We will use Codable and JSON to save and retrieve data from UserDefaults.

Before we begin let me caution you UserDefaults are not your database. Use CoreData or Realm for all your heavy lifting.

Make your class/Type conform to codable protocol

This is the first step. You need to make your Class and any nested object’s class conform to Codable protocol. It can be done as shown below

struct Product:Codable{
    var title:String?
    var description:String?
    var unitPrice:Double?
    var quantity:Double?
    var id: Int?
}

Saving Custom object to UserDefaults

In order to save the custom object, we need to convert it to data and save that data to UserDefaults. For this, we will use JSONEncoder

 let product = Product()      
 let data =  try! JSONEncoder().encode(product) //this is for demo use try properly
//Save the data to UserDefaults
 UserDefaults.standard.set(data, forKey: "PRODUCTS")

Retrieving custom object from UserDefaults

In order to retrieve the custom object from UserDefaults we will use JSONDecoder.

 let data = UserDefaults.standard.array(forKey: "PRODUCTS") as? Data;
  if data != nil{
       let product =  try! JSONDecoder().decode(Product.self, from: data)
      //use product
 }

So you have successfully saved and retrieved a custom swift object in UserDefault good job.

A pat on the back !!