NumberFormatter and unsigned with UInt64.max-CodePudding

I'm trying to create a string representing UInt64.max using NumberFormatter. Here's the code:

    let formatter = NumberFormatter()
    
    formatter.usesGroupingSeparator = true
    formatter.numberStyle = .decimal
    formatter.positiveFormat = "# ##0.#########"
    formatter.maximumSignificantDigits = 20
    formatter.usesSignificantDigits = false
    formatter.maximumFractionDigits = 20
    formatter.minimumFractionDigits = 0
    formatter.alwaysShowsDecimalSeparator = false
//    formatter.roundingMode = .halfUp

    let text1 = formatter.string(for: NSNumber(value: Int64.max))
    let text2 = formatter.string(for: NSNumber(value: UInt64.max))

    print(text1)
    print(text2)

which prints: Optional("9,223,372,036,854,780,000") Optional("-1")

text2 should 18,446,744,073,709,551,615, right?

It looks as if the NSNumber isn't taking the UIn64. The obj-c version (NSNumberFormatter) works fine.

Am I missing something or is there a problem with NumberFormatter?

CodePudding user response：

After some tinkering, found a solution:

let text2 = formatter.string(for: Decimal(UInt64.max))
print(text2)

This prints Optional("18,446,744,073,709,600,000")

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