JSONSerialization turns Bool value to NSNumber

eskimo · December 20, 2019, 9:17am

Well, that is how JSONSerialization works

Right. Due to its Objective-C heritage, it can’t return JSON Boolean values as Swift Bool values because those are value types, not objects.

What you’ll find, however, is that it does use CFBoolean for JSON Booleans, so you can detect whether the original was a Boolean or a number by testing against kCFBooleanTrue and kCFBooleanFalse. Consider:

// One of these 1’s is not like other…

let m = dictionary!["meta"]! as! [String:Any]
let d = m["demo"]! as! NSNumber
print(d)                        // 1
print(d === kCFBooleanTrue)     // true
print(d === kCFBooleanFalse)    // false

let e = dictionary!["employeeID"]! as! NSNumber
print(e)                        // 1
print(e === kCFBooleanTrue)     // false
print(e === kCFBooleanFalse)    // false

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Quinn “The Eskimo!” @ DTS @ Apple