Example of the Environment single for dependency injection and build configuration variants

Environment.swift

import Foundation

// Constant for configuration name from custom property in the Info.plist file
fileprivate let ConfigurationNameKey = "build.config"

// Singleton Instance used globally for shared resources and configuration
var ENV = Environment()

public struct Environment {
    public enum Configuration: String {
        case beta
        case production
    }
    public private(set) var date: () -> Date = Date.init
    public private(set) var configuration: Environment.Configuration = loadEnv()
}

extension Environment {
    private static func loadEnv() -> Environment.Configuration {
        guard let rawValue = Bundle.main.object(forInfoDictionaryKey: ConfigurationNameKey)
            as? String  else {  return .production }
        return Environment.Configuration(rawValue: rawValue) ?? .production
    }
}

extension Environment.Configuration {
    public var baseURL: URL {
        switch self {
        case .beta: return URL(string: "https://dev.example.com/")!
        case .production: return URL(string: "https://example.com/")!
        }
    }
}