Swift 3 - Pass Dictionary inside Array from JSON to Another Method - arrays

Question

I have the following JSON:
{
"stores":2,
"store_data":[
{
"store_id":1,
"store_name":"Target"
"store_color":"000000"
},
{
"store_id":2,
"store_name":"Walmart"
"store_color":"FFFFFF"
}
]
}
And I am collecting it (within a function) the following way (safeguards removed for simplicity):
let task = URLSession.shared.dataTask(with: baseURL) { (data, response, error) in
if let tmpRawData: NSDictionary = try JSONSerialization.jsonObject(with: data, options: JSONSerialization.ReadingOptions.mutableContainers) as! NSDictionary {
process(rawData: tmpRawData)
}
}
And sending it to the helper process function defined as:
func process(rawData: NSDictionary) -> Bool {
if let storeDataArray = rawData["store_data"] {
// Here I want to loop through the store_data array
}
}
And I am having some trouble looping through the array in the function above. Initially, I had tried:
for store: Dictionary<String, String> in storeDataArray {
// Do things with store["store_id"] here
}
But I am new to swift and am having trouble deciphering between NSArray, Array, Dictionary, NSDictionary, etc. I'm working in Swift 3. Any help is much appreciated!

Answer 1

First of all, don't annotate types that much. The compiler will tell you if it needs an explicit annotation
Second of all it's convenient to declare a type alias for a JSON dictionary
typealias JSONObject = [String:Any]
This is the task, tmpRawData is a dictionary – represented by {} in the JSON.
let task = URLSession.shared.dataTask(with: baseURL) { (data, response, error) in
if let tmpRawData = try JSONSerialization.jsonObject(with: data, options: []) as! JSONObject {
process(rawData: tmpRawData)
}
}
and the process function, the type alias makes everything more readable.
The value of rawData is an array of dictionaries – represented by [] in the JSON.
func process(rawData: JSONObject) -> Bool {
if let storeDataArray = rawData["store_data"] as? [JSONObject] {
for store in storeDataArray {
let storeID = store["store_id"] as! Int
let storeName = store["store_name"] as! String
let storeColor = store["store_color"] as! String
print(storeID, storeName, storeColor)
}
}
}
I have no idea why all tutorials suggests the mutableContainers option. You don't need it at all in Swift when using native collection types.