Having trouble loading custom data from firebase using swift - swift

Question

I followed the directions on the firebase website and came up with the code below labeled NEW CODE. The error I am getting is:
Cannot invoke initializer for type 'Result' with an argument list of type '(#escaping () throws -> CombinedModel?)'
I have tried researching about the Result object and this error but have not found anything that would help me directly. I was able to read the data using the old way (which I will post below), but am trying to follow Googles documentation
(https://firebase.google.com/docs/firestore/query-data/get-data)
Any help would be appreciated, thank you!
OLD CODE
func readData(word: String) -> CombinedModel? {
print("reading data")
let docRef = db.collection(K.FBConstants.dictionaryCollectionName).document(word)
var wordResults: CombinedModel? = nil
docRef.getDocument { (document, error) in
if let e = error {
print("Error loading data: \(e)")
return
} else {
do {
if let resultData = try document?.data(as: CombinedModel.self){
print("Definitions: \(resultData.definitionsArray)")
print("\n Synonyms: \(resultData.synonyms)")
wordResults = resultData
}
} catch {
print("Error decoding: \(error)")
}
}
}
return wordResults
}
NEW CODE
func newReadData(word: String) -> CombinedModel? {
let docRef = db.collection(K.FBConstants.dictionaryCollectionName).document(word)
docRef.getDocument { (document, error) in
let result = Result {
try document.flatMap {
try $0.data(as: CombinedModel.self)
}
}
switch result {
case .success(let combinedModel):
if let combinedModel = combinedModel {
print("CombinedModel: \(combinedModel)")
} else {
print("Document does not exist")
}
case .failure(let error):
print("Error decoding city: \(error)")
}
}
}
Here is the codable custom class I created for reading the data.
struct CombinedModel: Codable {
var definitionsArray: [WordModel]
var synonyms: [String]
private enum CodingKeys: String, CodingKey {
case definitionsArray
case synonyms
}
}
struct WordModel: Codable {
let id: String
let partOfSpeech: String
let definitions: [String]
let example: [String]
let ipa: String
let audio: String
private enum CodingKeys: String, CodingKey {
case id
case partOfSpeech
case definitions
case example
case ipa
case audio
}
}
struct ThesaurusModel: Codable {
var synonyms: [String]
private enum CodingKeys: String, CodingKey {
case synonyms
}
}

Answer 1

I realized the issue with the Result object was that Xcode was reading it as a structure that I created in a different file, but once I changed the name of that structure(it was named Result previously), it recognized the Result object as the correct object which is of type: enum Result where Failure : Error

Answer 2

Looks like you're getting close - minus the type error. From what I can tell, your error:
Cannot invoke initializer for type 'Result' with an argument list of type '(#escaping () throws -> CombinedModel?)'
Refers to this portion of code:
let result = Result {
try document.flatMap {
try $0.data(as: CombinedModel.self)
}
}
At least, this is the portion of code that looks off to me. Your (document, error) variable as a whole represents your result. You shouldn't need a Result middleman.
The real focus should be around determining whether or not there is an error. If there isn't you should read the document.
A working approach should look something like this:
func newReadData(word: String) -> CombinedModel? {
let docRef = db.collection(K.FBConstants.dictionaryCollectionName).document(word)
docRef.getDocument { (document, error) in
guard let fbDoc = document else {
// document is nil, parse the error object and handle it.
}
if let resultData = try fbDoc?.data(as: CombinedModel.self) {
return resultData
} else {
return nil
}
}
}
Let me know how that goes for you! Best of luck.