swift 将模型转换成JSONString

给Encodable扩展一个toJSONString()方法

public extension Encodable {
    
    func toJSONString() -> String {
        let encoder = JSONEncoder()
        encoder.outputFormatting = .prettyPrinted
        guard let data = try? encoder.encode(self) else{ return "" }
        guard let jsonStr = String(data: data, encoding: .utf8) else{ return "" }
        return jsonStr
    }
}

建立一个模型，遵守Codable(Decodable & Encodable)协议

struct TestModel: Codable {
    var name: String = ""
    var age: Int = 0
}

使用：

let testModel = TestModel(name: "name1", age: 10)
debugPrint(testModel.toJSONString())

输出：

"{\"name\":\"name1\",\"age\":10}"