how to handle the nil value variables

Question

I have model as below.

struc Info: Decodable {
    var firstName: String?
    var lastName: String?
}

While displaying in tableview cell, w

Answer 1

I would recommend one of two options:

1. Add computed property to the struct to determine the display name.
2. Manually decode, providing default values. (And also add a display name property if you want)

Personally, I like option 1. I think it's the most compact and also the easiest to maintain.

Option 1 Example:

struct Info1: Decodable {
    var firstName: String?
    var lastName: String?

    var displayName: String {
        return [self.firstName, self.lastName]
            .compactMap { $0 } // Ignore 'nil'
            .joined(separator: " ") // Combine with a space
    }
}

print(Info1(firstName: "John", lastName: "Smith").displayName)
// Output: "John Smith"

print(Info1(firstName: "John", lastName: nil).displayName)
// Output: "John"

print(Info1(firstName: nil, lastName: "Smith").displayName)
// Output: "Smith"

print(Info1(firstName: nil, lastName: nil).displayName)
// Output: ""

Option 2 Example:

struct Info2: Decodable {
    var firstName: String
    var lastName: String

    enum CodingKeys: String, CodingKey {
        case firstName, lastName
    }

    init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)

        self.firstName = try container.decodeIfPresent(String.self, forKey: .firstName) ?? ""
        self.lastName = try container.decodeIfPresent(String.self, forKey: .lastName) ?? ""
    }

    // Optional:
    var displayName: String {
        return [self.firstName, self.lastName]
            .compactMap { $0.isEmpty ? nil : $0 } // Ignore empty strings
            .joined(separator: " ") // Combine with a space
    }

    // TEST:
    init(from dict: [String: Any]) {
        let data = try! JSONSerialization.data(withJSONObject: dict, options: .prettyPrinted)
        self = try! JSONDecoder().decode(Info2.self, from: data)
    }
}

print(Info2(from: ["firstName": "John", "lastName": "Smith"]).displayName)
// Output: "John Smith"

print(Info2(from: ["lastName": "Smith"]).displayName)
// Output: "Smith"

print(Info2(from: ["firstName": "John"]).displayName)
// Output: "John"

print(Info2(from: [String: Any]()).displayName)
// Output: ""