How to fix 'appendingPathComponent' is unavailable: Use appendingPathComponent on URL error - swift4

Question

I'm working on a old Swift tutorial (Swift 2.0) that's posted on Ray Wenderlich's web site (https://www.raywenderlich.com/2185-how-to-make-a-letter-word-game-with-uikit-and-swift-part-3-3) and I'm running into an error when I tried to re-setup a function called "preloadAudioEffects" in Swift 4.2 . The error? appendingPathComponent' is unavailable: Use appendingPathComponent on URL instead.
I've tried to rename the old Swift code [Ex: NSBundle to Bundle , stringByAppendingPathComponent to appendingPathComponent()], but I'm still running into some syntax issues due to my inexperience with Swift.
This is the original code:
func preloadAudioEffects(effectFileNames:[String]) {
for effect in AudioEffectFiles {
//1 get the file path URL
let soundPath = NSBundle.mainBundle().resourcePath!.stringByAppendingPathComponent(effect)
let soundURL = NSURL.fileURLWithPath(soundPath)
//2 load the file contents
var loadError:NSError?
let player = AVAudioPlayer(contentsOfURL: soundURL, error: &loadError)
assert(loadError == nil, "Load sound failed")
//3 prepare the play
player.numberOfLoops = 0
player.prepareToPlay()
//4 add to the audio dictionary
audio[effect] = player
}
}
And this is what I've tried to do via following the suggestions in Xcode:
func preloadAudioEffects(effectFileNames:[String]) {
for effect in AudioEffectFiles {
//1 get the file path URL
let soundPath = Bundle.main.resourcePath!.appendingPathComponent(effect)
let soundURL = NSURL.fileURL(withPath: soundPath)
//2 load the file contents
var loadError:NSError?
let player = AVAudioPlayer(contentsOfURL: soundURL, error: &loadError)
assert(loadError == nil, "Load sound failed")
//3 prepare the play
player.numberOfLoops = 0
player.prepareToPlay()
//4 add to the audio dictionary
audio[effect] = player
}
}
Get the full path to the sound file and convert it to a URL by using NSURL.fileURLWithPath().
Call AVAudioPlayer(contentsOfURL:error:) to load a sound file in an audio player.
Set the numberOfLoops to zero so that the sound won’t loop at all. Call prepareToPlay() to preload the audio buffer for that sound.
Finally, save the player object in the audio dictionary, using the name of the file as the dictionary key.

Answer 1

Just replace resourcePath with resourceURL
let soundURL = Bundle.main.resourceURL!.appendingPathComponent(effect)
and you have to wrap the AVAudioPlayer initializer in a try block
func preloadAudioEffects(effectFileNames:[String]) {
for effect in AudioEffectFiles {
let soundURL = Bundle.main.resourceURL!.appendingPathComponent(effect)
//2 load the file contents
do {
let player = try AVAudioPlayer(contentsOf: soundURL)
//3 prepare the play
player.numberOfLoops = 0
player.prepareToPlay()
//4 add to the audio dictionary
audio[effect] = player
} catch { print(error) }
}
}