quoteTest.swift

import UIKit

struct Quote: Decodable {
    let symbol: String
    let companyName: String
    let primaryExchange: String
    let sector: String
    let calculationPrice: String
    let open: Double
    let openTime: Int
    let close: Double
    let closeTime: Int
    let high: Double
    let low: Double
    let latestPrice: Double
    let latestSource: String
    let latestTime: String
    let latestUpdate: Int
    let latestVolume: Double
    let iexRealtimePrice: Double
    let iexRealtimeSize: Double
    let iexLastUpdated: Int
    let delayedPrice: Double
    let delayedPriceTime: Int
    let extendedPrice: Double
    let extendedChange: Double
    let extendedChangePercent: Double
    let extendedPriceTime: Int
    let previousClose: Double
    let change: Double
    let changePercent: Double
    let iexMarketPercent: Double
    let iexVolume: Double
    let avgTotalVolume: Double
    let iexBidPrice: Double
    let iexBidSize: Double
    let iexAskPrice: Double
    let iexAskSize: Double
    let marketCap: Double
    let peRatio: Double
    let week52High: Double
    let week52Low: Double
    let ytdChange: Double
}

let data = try! Data(contentsOf: URL(string:"https://api.iextrading.com/1.0/stock/market/batch?symbols=aapl,fb&types=quote")!)

let response = try JSONDecoder().decode([String:[String: Quote]].self,from: data)
let apple = response["AAPL"]
let appleQuote = apple!["quote"]

print(appleQuote!)

// ## With URLSession
let session = URLSession.shared
let dataTask = session.dataTask(with: url) { (data, response, error) in
    guard  let data = data, error == nil else { return }
    let response = try! JSONDecoder().decode([String:[String: Quote]].self,from: data)
    let apple = response["FB"]
    let appleQuote = apple!["quote"]
    print(appleQuote!)
}

dataTask.resume()