Swift 5 - JSONEncoder with nested JSON-CodePudding

I'm trying to encode a [[String : String]] into JSON nested objects with JSONEncoder().

Example of Swift output:

[["firstName": "John", "lastName": "Doe"], ["firstName": "Tim", "lastName": "Cook"]]

Intended output of JSON after being encoded:

[
  {
    "firstName": "John",
    "lastName": "Doe"
  },

  {
    "firstName": "Tim",
    "lastName": "Cook"
  }
]

How would I go about looping through this array of dictionaries and then encoding it with JSONEncoder().encode()? Thanks so much!

CodePudding user response：

JSONEncoder gives you Data by default. To get it back into String form, you can use this:

let input = [["firstName": "John", "lastName": "Doe"], ["firstName": "Tim", "lastName": "Cook"]]

do {
    let json = try JSONEncoder().encode(input)
    print(String(decoding: json, as: UTF8.self))
} catch {
    print(error)
}

Which yields:

[{"firstName":"John","lastName":"Doe"},{"firstName":"Tim","lastName":"Cook"}]

CodePudding user response：

Using Codable to encode/decode JSON data. Firstly, convert JSON into an object like this, it will make it easier if you update with more fields:

struct Person: Codable {
    var firstName: String
    var lastName: String
}

Assume that you have a Person array

var persons = [Person]()
persons.append(.init(firstName: "John", lastName: "Doe"))
persons.append(.init(firstName: "Tim", lastName: "Cook"))

//PRINT OUT
let jsonData = try! JSONEncoder().encode(persons)
let jsonString = String(data: jsonData, encoding: .utf8)

And this is the output:

"[{"firstName":"John","lastName":"Doe"},{"firstName":"Tim","lastName":"Cook"}]"