Bad CSV Parser in swift

BadCSVParser.swift

// Quick and dirty CSV parser I wrote. Handles edge cases badly. Doesn't perform well. Doesn't handle large csv files.
// But, hey, it solved my use case!
// Swift 4.2+

func parseCSVBadly(csvData: Data) -> [[String]] {
    guard let csv = String(data: csvData, encoding: .utf8) else { return [] }
    return csv.components(separatedBy: CharacterSet.newlines).compactMap { line in
        guard !line.hasPrefix("#") else { return nil }
        return line.components(separatedBy: ",")
    }
}

import Quick
import Nimble

final class CSVParserSpec: QuickSpec {
    override func spec() {
        it("Parses csvs") {
            let data = "a,b,c,d\ne,f".data(using: .utf8)!
            
            expect(
                parseCSVBadly(csvData: data)
            ).to(equal([["a", "b", "c", "d"], ["e", "f"]]))
        }
        
        it("ignores lines prefixed with '#'s") {
            let data = """
a,b,c,d
# whatever.
e,f,g
""".data(using: .utf8)!
            expect(
                parseCSVBadly(csvData: data)
            ).to(equal([["a", "b", "c", "d"], ["e", "f", "g"]]))
        }
    }
}