Abbreviated date interval String formatting

MyModel.swift

var timeString: String {
    let formatter = DateComponentsFormatter()
    formatter.allowedUnits = [.month, .day, .hour, .minute]
    formatter.unitsStyle = .abbreviated
    formatter.zeroFormattingBehavior = .dropAll

    if let date = self.date, let interval = formatter.string(from: date, to: Date()) {
        return "\(interval) ago"
    }
    return "unknown"
}