Check if array is Codable

Question

I have a function below:

func check(_ type: Any.Type) {
        switch type {
           case is [String].Type
        ...
      }
}

For example:

class TaskContainer: Codable {
    let id: String
    let tasks: [String]
}
typealias TaskContainers = [TaskContainer]
check(TaskContainers.self)

How to check if an array is Codable?

Not working:

Why do you need to check that? You made the array; how can you not know whether its element is Codable? — matt
– matt, Commented Apr 26, 2018 at 20:13
You seem to be assuming that [TaskContainer].Type is a subtype of [Codable].Type, but it is not. What you are trying to do is highly unusual. If you tell us more about why you want to do this, maybe we can suggest a better way. — rob mayoff
– rob mayoff, Commented Apr 26, 2018 at 20:24
Almost anything you try here is likely to be unreliable, even if you get it working. Much of Swift is statically dispatched, so it will make choices at compile-time, not runtime. The fact that you are passing around Any.Type at all suggests a very deep type problem in your code. You should back up and think through the problem you're actually trying to solve, and we should be able to help you. — Rob Napier
– Rob Napier, Commented Apr 26, 2018 at 20:25
@robmayoff, it's a function in PerfectPostgreSQL. I need to add new type(Array of Codable objects) / — user3166661
– user3166661, Commented Apr 26, 2018 at 20:29
I took a quick look at Perfect-PostgreSQL and found no functions named check. Edit your question to show us how you're trying to use the library and what errors are occurring. — rob mayoff
– rob mayoff, Commented Apr 26, 2018 at 20:32

Hamer · Accepted Answer · 2018-04-26 20:20:12Z

1

I'm not sure the reason for checking but this should work.

if let _ = TaskContainers.self as? Codable.Type {
    // Conforms to Codable protocol.
}

answered Apr 26, 2018 at 20:20

Hamer

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