Pretty Print | Pretty JSON Stringify in Swift

pretty_json_stringify.swift

import Foundation

typealias MyObject = [String: Any?]
typealias MyArray = [Any?]

func prettyJsonStringify(_ anything: Any? = nil, indent: String = "    ") -> String {
    var indentLevel = 0
    func prettyJsonStringifyInner(_ anythingInner: Any?, _ indentInner: String) -> String {
        guard let anythingInner = anythingInner else {
            return "null"
        }
        if let anythingInner = anythingInner as? String {
            return "\"\(anythingInner)\""
        }
        if let anythingInner = anythingInner as? Bool {
            return "\(anythingInner)"
        }
        if let anythingInner = anythingInner as? NSNumber {
            return "\(anythingInner)"
        }
        if let anythingInner = anythingInner as? MyArray {
            if (anythingInner.count == 0) {
                return "[]"
            }
            indentLevel += 1
            var result = "[\n\(String(repeating: indentInner, count: indentLevel))"
            for (arrayItemIndex, arrayItem) in anythingInner.enumerated() {
                result += prettyJsonStringifyInner(arrayItem, indentInner)
                if ((arrayItemIndex + 1) != anythingInner.count) {
                    result += ",\n\(String(repeating: indentInner, count: indentLevel))"
                }
            }
            indentLevel -= 1
            result += "\n\(String(repeating: indentInner, count: indentLevel))]"
            return result
        }
        if let anythingInner = anythingInner as? MyObject {
            if (anythingInner.count == 0) {
                return "{}"
            }
            indentLevel += 1
            var result = "{\n\(String(repeating: indentInner, count: indentLevel))"
            for (entryIndex, (objectKey, objectValue)) in anythingInner.enumerated() {
                result += "\"\(objectKey)\": \(prettyJsonStringifyInner(objectValue, indentInner))"
                if ((entryIndex + 1) != anythingInner.count) {
                    result += ",\n\(String(repeating: indentInner, count: indentLevel))"
                }
            }
            indentLevel -= 1
            result += "\n\(String(repeating: indentInner, count: indentLevel))}"
            return result
        }
        return "null"
    }
    return prettyJsonStringifyInner(anything, indent)
}

let products: MyArray = [
    [
        "id": "P1",
        "name": "bubble gum"
    ] as MyObject,
    [
        "id": "P2",
        "name": "potato chips"
    ] as MyObject
]
print("products: \(prettyJsonStringify(products))")