SwiftUI extension Bundle for parse JSON file All In One

JSONDecoder


//
//  CodableBundle.swift
//  PlacesOfInterest
//
//  Created by xgqfrms on 2022/6/1.
//

import Foundation

// 扩展原有的 Bundle ✅
extension Bundle {
  // Extensions must not contain stored properties
  // private let step1Error = "加载本地 json 文件 ❌";
  // 解析 json 文件
  func decode(_ fileName: String) -> [CoverModel] {
    // 1. 加载本地 json 文件
    guard let url = self.url(forResource: fileName, withExtension: nil) else {
      let error = "加载本地 json 文件 ❌, fileName: \(fileName)";
      print(error)
      fatalError(error)
    }
    // 2. 读取数据
    guard let data = try? Data(contentsOf: url) else {
      let error = "读取数据 ❌, fileName: \(fileName)";
      print(error)
      fatalError(error)
    }
    // 3. 解析 JSON 数据
    guard let json = try? JSONDecoder().decode([CoverModel].self, from: data) else {
      let error = "解析 JSON 数据 ❌, fileName: \(fileName)";
      print(error)
      fatalError(error)
    }
    return json;
  }
}

demo

<T: Decodable> T.Type -> T T.self


extension Bundle {
    // 泛型 T，动态类型 
    func decode<T: Decodable>(_ type: T.Type, from filename: String) -> T {
        guard let json = url(forResource: filename, withExtension: nil) else {
            fatalError("Failed to locate \(filename) in app bundle.")
        }
        guard let data = try? Data(contentsOf: json) else {
            fatalError("Failed to load \(filename) from app bundle.")
        }
        let decoder = JSONDecoder();
        guard let json = try? decoder.decode(T.self, from: data) else {
            fatalError("Failed to decode \(filename) from app bundle.")
        }
        return json
    }
}


// demo
let items = Bundle.main.decode([TourItem].self, from: "Tour.json")