Setting default values for NSUserDefaults

NSUserDefaults.swift

/*
UserDefaults (NSUserDefaults) is a go-to database for saving users' preferences over application behavior, 
e.g., font size, sound disable/enable. So, most of the time, you want each of them to have a default value.
*/

// Basic approach

let userDefaults = UserDefaults.standard

// 1
if userDefaults.value(forKey: "enabledSound") == nil {
    userDefaults.set(true, forKey: "enabledSound")
}

// 2
if userDefaults.value(forKey: "enabledVibration") == nil {
    userDefaults.set(true, forKey: "enabledVibration")
}


// The right approach with register(defaults:)

let userDefaults = UserDefaults.standard

// 1
userDefaults.register(
    defaults: [
        "enabledSound": true,
        "enabledVibration": true
    ]
)

print(userDefaults.bool(forKey: "enabledSound")) // print true


// The value is only set if the key is nil

let userDefaults = UserDefaults.standard

// 1
userDefaults.set(false, forKey: "enabledSound")

// 2
userDefaults.register(
    defaults: [
        "enabledSound": true,
        "enabledVibration": true
    ]
)

print(userDefaults.bool(forKey: "enabledSound")) // print false


// The default values are not persist

let userDefaults = UserDefaults.standard

print(userDefaults.integer(forKey: "counter")) // print 0

// 1
userDefaults.register(
    defaults: [
        "counter": 5
    ]
)

print(userDefaults.integer(forKey: "counter")) // print 5

//