Is there a way to pretty print Swift dictionaries to the console?

Question

NSDictionary *dictionary = @{@\"A\" : @\"alfa\",
                             @\"B\" : @\"bravo\",
                             @\"C\" : @\"charlie\",
                       


        

Answer 1

Adjusted based on my other answer here.

PrettyPrint JSON solution using LLDB alias

✨No code needed ✨

• To get a nice json formatting (indentations, newlines, etc) you can define an lldb alias by running this command in your lldb terminal (source):

command regex pjson 's/(.+)/expr print(NSString(string: String(data: try! JSONSerialization.data(withJSONObject: %1, options: .prettyPrinted), encoding: .utf8)!))/'

• You probably don't want to re-define the alias everytime you open XCode, so run the following command to append the alias definition to ~/.lldbinit:

echo "command regex pjson 's/(.+)/expr print(NSString(string: String(data: try! JSONSerialization.data(withJSONObject: %1, options: .prettyPrinted), encoding: .utf8)!))/'" >> ~/.lldbinit

• This will create the pjson alias which you can use in your lldb terminal in XCode:

pjson object

---

Comparing the outputs for the following Swift object:

// Using Any? to demo optional & arbitrary Type
let dictionary: Any? = [
    "embedded": [
        "JustForTheSakeOfTheDemo": 42
    ],
    "A" : "alfa",
    "B" : "bravo",
    "C" : "charlie",
    "D" : "delta",
    "E" : "echo",
    "F" : "foxtrot"
]

✅ Output of pjson dictionary

{
  "F" : "foxtrot",
  "D" : "delta",
  "embedded" : {
    "JustForTheSakeOfTheDemo" : 42
  },
  "E" : "echo",
  "A" : "alfa",
  "C" : "charlie",
  "B" : "bravo"
}

❌ Output of p dictionary

(Any?) $R0 = 7 key/value pairs {
  [0] = {
    key = "F"
    value = "foxtrot"
  }
  [1] = {
    key = "D"
    value = "delta"
  }
  [2] = {
    key = "embedded"
    value = 1 key/value pair {
      [0] = (key = "JustForTheSakeOfTheDemo", value = 42)
    }
  }
  [3] = {
    key = "E"
    value = "echo"
  }
  [4] = {
    key = "A"
    value = "alfa"
  }
  [5] = {
    key = "C"
    value = "charlie"
  }
  [6] = {
    key = "B"
    value = "bravo"
  }
}

❌ Output of p (dictionary as! NSDictionary)

(NSDictionary) $R18 = 0x0000000281e89710 {
  ObjectiveC.NSObject = {
    base__SwiftNativeNSDictionaryBase@0 = {
      baseNSDictionary@0 = {
        NSObject = {
          isa = Swift._SwiftDeferredNSDictionary with unmangled suffix "$"
        }
      }
    }
  }
}

❌ Output of po dictionary

▿ Optional
  ▿ some : 7 elements
    ▿ 0 : 2 elements
      - key : "F"
      - value : "foxtrot"
    ▿ 1 : 2 elements
      - key : "D"
      - value : "delta"
    ▿ 2 : 2 elements
      - key : "embedded"
      ▿ value : 1 element
        ▿ 0 : 2 elements
          - key : "JustForTheSakeOfTheDemo"
          - value : 42
    ▿ 3 : 2 elements
      - key : "E"
      - value : "echo"
    ▿ 4 : 2 elements
      - key : "A"
      - value : "alfa"
    ▿ 5 : 2 elements
      - key : "C"
      - value : "charlie"
    ▿ 6 : 2 elements
      - key : "B"
      - value : "bravo"

❌ Output of po print(dictionary)

Optional(["F": "foxtrot", "D": "delta", "embedded": ["JustForTheSakeOfTheDemo": 42], "E": "echo", "A": "alfa", "C": "charlie", "B": "bravo"])