Localizable String Extensions

String+Localized.swift

//
//  String+Localized.swift
//
//  Created by Jan Cássio on 2021/03/27.
//  Copyright © 2021 Jan Cassio. All rights reserved.
//

import Foundation

extension String {
  /**
    # Localized
    Return a localized text for a given string.
    
    ### Example:
    
    ```
    "key_for_a_localized_string".localized() // return the localized string for given string.
    ```
    
    - Parameters:
      - in: The Bundle where the Localizable.strings are, default is .main.
      - value: Used as fallback value. Default is `""`
      - comment: An addition string to describe the text. Default is `""`.
    
    - Returns:
      the localized string, otherwise returns the string assigned to `value` parameter.
    
    */
  func localized(in bundle: Bundle = .main, value: String = "", comment: String = "") -> String {
      return NSLocalizedString(
          self,
          bundle: bundle,
          value: value,
          comment: comment
      )
  }
}

/**
# StringLocalizable Protocol

StringLocalizable enable to some type to use any enumerator of string as a source of strong typed localized strings.

In the example below, each case in `Localized Keys` is a key for a localized string hosted in the main bundle.

```
enum LocalizedKeys: String {
  case title
  case subtitle
}

extension MyView {
  typealias Options = LocalizedKeys
    
  func localized(_ key: Options) -> String {
      return key.rawValue.localized()
    }
}

// anywhere in the MyView, you could obtain localized string just doing this:

let title = localized(.title) // string for "title" key
let subitle = localized(.subtitle) // string for "title" key

*/
protocol StringLocalizable {
  /** Options could be any Enum raw representable by `String` type. */
  associatedtype Options: RawRepresentable where Options.RawValue == String
  
  /**
    # Localized
    Get the localized string from the given Option
    
    - Returns:
    A localized string or a empty string if the key was not found.
    */
  func localized(_ key: Options) -> String
}