Swift 4 handling nil values from Firestore with CodableFirebase and custom classes

Question

I'm using the library CodableFirebase to decode and encode data when working with Google's Firestore. It works great, except if a value is not defined in the database but is a property of the class. I am wondering how do you define the class so that when the snapshot comes back from Firebase it doesn't puke on the nil value.

Here's a simple example of what is happening.. This would be my class definition.

class TimeThing: Codable {
 var requestedTime: Double?
 var createdTime: Double?

 init(
    requestedTime: Double? = 0,
    createdTime: Double? = 0
    ) {
     self.requestedTime = requestedTime
     self.createdTime = createdTime
}}

And this would be the error that's getting thrown. createdTime, in this case, has a value in Firestore where 'requestedTime' doesn't.

Thread 1: Fatal error: 'try!' expression unexpectedly raised an error: Swift.DecodingError.typeMismatch(Swift.Double, Swift.DecodingError.Context(codingPath: [CodingKeys(stringValue: "requestedTime", intValue: nil)], debugDescription: "Expected to decode Double but found a string/data instead.", underlyingError: nil))

I realize I'm missing something fundamental, but unfortunately I'm just not sure what that is. What do I need to do to my class to set defaults that will not blow up my try block when experiencing a nil value from Firestore?

Thanks!!

Answer 1

Turns out the core of the issue was that the defaults in the class were incorrectly defined.

class TimeThing: Codable {
 var requestedTime: Double?
 var createdTime: Double?

 init(
    requestedTime: Double? = 0,
    createdTime: Double? = 0
    ) {
     self.requestedTime = requestedTime
     self.createdTime = createdTime
}}

should have been

class TimeThing: Codable {
 var requestedTime: Double? = 0
 var createdTime: Double? = 0

 init(
    requestedTime: Double,
    createdTime: Double
    ) {
     self.requestedTime = requestedTime
     self.createdTime = createdTime
}}

Once I fixed that, the defaults were there for CodableFirebase to decode.