macOS command line program to convert HEIC images to JPGs

heic2jpg.swift

import Foundation
import Cocoa

guard CommandLine.arguments.count > 1 else {
    fatalError("Usage: heic2jpg <folder>")
}

let folder = CommandLine.arguments[1]

guard let files = try? FileManager().contentsOfDirectory(atPath: folder) else {
    fatalError("Unable to get files from \(folder)")
}

files.forEach { file in
    
    guard file.hasSuffix(".HEIC") else {
        return
    }
    
    let imageFile = "\(folder)/\(file)"
    
    guard let image = NSImage(contentsOfFile: imageFile) else {
        fatalError("Failed to read \(imageFile)")
    }
    
    guard let bits = image.representations.first as? NSBitmapImageRep else {
        fatalError("Couldn't get image data for \(imageFile)")
    }
    
    guard let data = bits.representation(using: .jpeg, properties: [:]) else {
        fatalError("Couldn't convert \(imageFile) to jpg")
    }

    let jpg = file.dropLast(4).appending("jpg")
    let targetFile = "\(folder)/\(jpg)"
    let targetFileUrl = URL(fileURLWithPath: targetFile)
    
    print("Writing", targetFile)
    try! data.write(to: targetFileUrl, options: [ .atomic])
    
}