How to get an Array of Objects from Firestore in Swift?

Question

In Swift, to retrieve an array from Firestore I use:

currentDocument.getDocument { (document, error) in
  if let document = document, document.exists {
    let people = document.data()!["people"]
    print(people!)
  } else {
    print("Document does not exist")
  }
}

And I receive data that looks like this


(
  {
    name = "Bob";
    age = 24;
  }
)

However, if I were to retrieve the name alone, normally I'd do print(document.data()!["people"][0]["name"]).

But the response I get is Value of type 'Any' has no subscripts

How do I access the name key inside that object inside the people array?

Frank van Puffelen · Accepted Answer · 2019-03-27 02:23:22Z

8

The value returned by document.data()!["people"] is of type Any and you can't access [0] on Any.

You'll first need to cast the result to an array, and then get the first item. While I'm not a Swift expert, it should be something like this:

let people = document.data()!["people"]! as [Any]
print(people[0])

edited Mar 27, 2019 at 2:23

answered Mar 27, 2019 at 1:39

Frank van Puffelen

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5 Comments

Richard Reis Over a year ago

This crashed the app and gave me this error Could not cast value of type '__NSArrayM' to 'NSDictionary' do you know how to solve it?

Frank van Puffelen Over a year ago

Yeah, I think I accidentally made it a dictionary. I updated my answer, but I'd definitely also recommend searching for these error messages (as that's pretty much what I'm doing).

Richard Reis Over a year ago

This worked! Thank you. And I do look up these error messages but sometimes don't understand them. For example, your solution gives me the people[0] result. But when I try to get people[0]["name"] it tells me Cannot subscript a value of type '[Any]' with an index of type 'String'

Richard Reis Over a year ago

So I try to turn [Any] into [Any : String] but I get Type 'Any' does not conform to protocol 'Hashable'... This is how I get stuck...

Frank van Puffelen Over a year ago

people[0] is a dictionary, where each key is string and the value is any type (since it can be both a string and a number). So people[0] as [String: Any] is the correct conversion there.

Ken Mueller · Accepted Answer · 2019-04-06 16:19:57Z

4

A better way of writing @Frank van Puffelen's answer would be:

currentDocument.getDocument { document, error in
  guard error == nil, let document = document, document.exists, let people = document.get("people") as? [Any] else { return }
    print(people)
  }
}

The second line may be a little long, but it guards against every error possible.

answered Apr 6, 2019 at 16:19

Ken Mueller

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