Git Product home page Git Product logo

mapper's Introduction

Mapper

Mapper is a simple Swift library to convert JSON to strongly typed objects. One advantage to Mapper over some other libraries is you can have immutable properties.

Installation

use_frameworks!

pod "ModelMapper"
github "lyft/mapper"

Usage

Simple example:

import Mapper
// Conform to the Mappable protocol
struct User: Mappable {
  let id: String
  let photoURL: URL?

  // Implement this initializer
  init(map: Mapper) throws {
    try id = map.from("id")
    photoURL = map.optionalFrom("avatar_url")
  }
}

// Create a user!
let JSON: NSDictionary = ...
let user = User.from(JSON) // This is a 'User?'

Using with enums:

enum UserType: String {
  case Normal = "normal"
  case Admin = "admin"
}

struct User: Mappable {
  let id: String
  let type: UserType

  init(map: Mapper) throws {
    try id = map.from("id")
    try type = map.from("user_type")
  }
}

Nested Mappable objects:

struct User: Mappable {
  let id: String
  let name: String

  init(map: Mapper) throws {
    try id = map.from("id")
    try name = map.from("name")
  }
}

struct Group: Mappable {
  let id: String
  let users: [User]

  init(map: Mapper) throws {
    try id = map.from("id")
    users = map.optionalFrom("users") ?? []
  }
}

Use Convertible to transparently convert other types from JSON:

extension CLLocationCoordinate2D: Convertible {
  static func fromMap(value: AnyObject?) throws -> CLLocationCoordinate2D {
    guard let location = value as? NSDictionary,
      let latitude = location["lat"] as? Double,
      let longitude = location["lng"] as? Double else
      {
         throw MapperError.convertibleError(value: value, type: [String: Double].self)
      }

      return CLLocationCoordinate2D(latitude: latitude, longitude: longitude)
  }
}

struct Place: Mappable {
  let name: String
  let location: CLLocationCoordinate2D

  init(map: Mapper) throws {
    try name = map.from("name")
    try location = map.from("location")
  }
}

let JSON = [
  "name": "Lyft HQ",
  "location": [
    "lat": 37.7603392,
    "lng": -122.41267249999999,
  ],
]

let place = Place.from(JSON)

Custom Transformations

private func extractFirstName(object: AnyObject?) throws -> String {
  guard let fullName = object as? String else {
    throw MapperError.convertibleError(value: object, type: String.self)
  }

  let parts = fullName.characters.split { $0 == " " }.map(String.init)
  if let firstName = parts.first {
    return firstName
  }

  throw MapperError.customError(field: nil, message: "Couldn't split the string!")
}

struct User: Mappable {
  let firstName: String

  init(map: Mapper) throws {
    try firstName = map.from("name", transformation: extractFirstName)
  }
}

Parse nested or entire objects

struct User: Mappable {
  let name: String
  let JSON: AnyObject

  init(map: Mapper) throws {
    // Access the 'first' key nested in a 'name' dictionary
    try name = map.from("name.first")
    // Access the original JSON (maybe for use with a transformation)
    try JSON = map.from("")
  }
}

See the docstrings and tests for more information and examples.

Open Radars

These radars have affected the current implementation of Mapper

  • rdar://23376350 Protocol extensions with initializers do not work in extensions
  • rdar://23358609 Protocol extensions with initializers do not play well with classes
  • rdar://23226135 Can't conform to protocols with similar generic function signatures
  • rdar://23147654 Generic functions are not differentiated by their ability to throw
  • rdar://23695200 Using the ?? operator many times is unsustainable.
  • rdar://23697280 Lazy collection elements can be evaluated multiple times.
  • rdar://23718307 Non final class with protocol extensions returning Self don't work

License

Mapper is maintained by Lyft and released under the Apache 2.0 license. See LICENSE for details

mapper's People

Contributors

austinate avatar keith avatar prayagverma avatar ryan-lane avatar

Watchers

 avatar

Recommend Projects

  • React photo React

    A declarative, efficient, and flexible JavaScript library for building user interfaces.

  • Vue.js photo Vue.js

    ๐Ÿ–– Vue.js is a progressive, incrementally-adoptable JavaScript framework for building UI on the web.

  • Typescript photo Typescript

    TypeScript is a superset of JavaScript that compiles to clean JavaScript output.

  • TensorFlow photo TensorFlow

    An Open Source Machine Learning Framework for Everyone

  • Django photo Django

    The Web framework for perfectionists with deadlines.

  • D3 photo D3

    Bring data to life with SVG, Canvas and HTML. ๐Ÿ“Š๐Ÿ“ˆ๐ŸŽ‰

Recommend Topics

  • javascript

    JavaScript (JS) is a lightweight interpreted programming language with first-class functions.

  • web

    Some thing interesting about web. New door for the world.

  • server

    A server is a program made to process requests and deliver data to clients.

  • Machine learning

    Machine learning is a way of modeling and interpreting data that allows a piece of software to respond intelligently.

  • Game

    Some thing interesting about game, make everyone happy.

Recommend Org

  • Facebook photo Facebook

    We are working to build community through open source technology. NB: members must have two-factor auth.

  • Microsoft photo Microsoft

    Open source projects and samples from Microsoft.

  • Google photo Google

    Google โค๏ธ Open Source for everyone.

  • D3 photo D3

    Data-Driven Documents codes.