10 Best Tips to Swift Development from Swift expert

1. For Loop vs While Loop

Example: Print “Count” 5 times

// Okay Code 
var i = 0 
while 5 > i {
   print("Count :\(i)”) 
   i += 1
}

You made the variable “i” to make sure your computer doesn’t break by printing limited numbers.

Listen, more variables → more memorization → more headache → more bugs → more life problems.

Remember the Butterfly effect.

//  Code

for i in 1...5 {
 print("Count  :\(i)”)
}

2. Optional Unwrapping

Example: Guard let vs if let

Let’s make a program for welcoming a new user.

var username: String?
var password: String?

// Hideous Code
func userLogIn() {
 if let uName = username {
  if let pwd = password {
   print("Welcome, \(uName)"!)
  }
 }
}

Do you see the pyramid of doom? Those are nasty nested code. Never. Destroy the bad, bring the good.

// Pretty Code

func userLogIn() {
 guard let uName = username, let pwd = password 
  else { return } 
 print("Welcome, \(uName)!") 
}

The difference is trendemous. If username or password has a nil value, the pretty code will early-exit the function by calling “return”. If not, it will print the welcoming message.

3. Extension

Example: Square a number

// Okay Version
func square(x: Int) -> Int { return x * x }
var squaredOfSix = square(x: 6)
square(x: squaredOfSix) // 625

The useless variable was created to double square 6— we need not enjoy typing.

//  Version

extension Int { 
 var squared: Int { return self * self }
}

6.squared // 36
6.squared.squared // 1296

4. Generics

Example: Print all elements in an array

//  Code

var arrString   = [“John Cena", “Tom Cruise", “Kristen Stewart"]
var arrInt		 = [4, 5, 6, 7, 8]
var arrDouble 	 = [6.0, 8.0, 10.0]

func printStringArray(arr: [String])
  for str in arr { 
    print(str) 
  } 
}

func printIntArray(arr: [Int]) {
  for i in arr {
    print(i)
  } 
}

func printDoubleArray(arr: [Double]) {
  for d in arr {
     print(d) 
  }
 }

Too many useless functions. Let’s create just one.

//  Code

func printElementFromArray(arr: [T]) {
  for element in arr { 
    print(element)  
  } 
}

5. Functional Programming

Example: Get even numbers

// Imperative 
var arrEvens : [Int] = []
for i in 1…20 {
 if i % 2 == 0 { arrEvens.append(i) } }
print(arrEvens) // [2, 4, 6, 8, 10, 12, 14, 16, 18, 20]

I don’t need to see the entire process. I am wasting my time reviewing how your for-loop looks like. Let’s make it explicit.

// Declarative 
var evens = Array(1…20).filter { $0 % 2 == 0 } 
print(evens) // [2, 4, 6, 8, 10, 12, 14, 16, 18, 20]

Functional Programming is phenomenal.
Functional Programming makes you look smart.

6. Closure vs Func

// Normal Function 
func sum(x: Int, y: Int) -> Int { return x + y }
var result = sum(x: 6, y: 8) // 14

You need not memorize the name of the function and the variable — You just need one.

// Closure
var sumUsingClosure: (Int, Int) -> (Int) = { $0 + $1 }
sumUsingClosure(6, 8) // 14

7. Computed Property vs Function

Example: finding a diameter of a circle

//  Code
func getDiameter(radius: Double) -> Double { return radius * 2}
func getRadius(diameter: Double) -> Double { return diameter / 2}

getDiameter(radius: 20) // return 40

getRadius(diameter: 400) // return 200

getRadius(diameter: 800) // return 400

You created two mutually exclusive functions. Atrocious. Let’s connect the dot between radius and diameter.

// Good Code
var radius: Double = 20
var diameter: Double {
 get { return radius * 2}
 set { radius = newValue / 2} 
} 

radius // 20

diameter // 40

diameter = 8000 

radius // 4000

Now, the radius and diameter variables are interdependent of each other. More connections → less extra typing → fewer typos → fewer bugs → fewer life problems.

8. Enum to Type Safe

Example: Ticket Selling

// Simply Bad

switch person {
 case "Adult": print("Pay $12”)
 case "Child": print("Pay $4”)
 case "Senior": print("Pay $8”)
 default: print("You alive, bruh?") }

“Adult”, “Child”, “Senior” → you are hard coding. You are literally typing all these string values for each case. That’s a no no. I explained what happens when you write too much. We never enjoy typing.

//  Code
enum People { case adult, child, senior }
var person = People.adult
switch person {
 case .adult: print("Pay $12”)
 case .child: print("Pay $4”)
 case .senior: print("Pay $8”)
}

You will never make a typo because “.adult”, “.child”, “.senior” highlight themselves. If the switch statement encountered unknown cases beyond the scope of the designated enum, Xcode would scream with that red error () on the left side. — I just couldn’t find the right emoji.

9. Nil Coalescing

Example: User choosing Twitter theme color

// Long Code
var userChosenColor: UIColor? 
var defaultColor = UIColor.red
var colorToUse = UIColor.clear
if let Color = userChosenColor { colorToUse = Color } else
 { colorToUse = defaultColor }

Too long. Let’s cut the fat.

// Concise AF
var colorToUse = userChosenColor ?? defaultColor

The code above states, if userChosenColor returns nil, choose defaultColor (red). If not, choose userChosenColor.

10. Conditional Coalescing

Example: Increase height if you have spiky hair

// Simply Verbose
var currentHeight = 160
var hasSpikyHair = true
var finalHeight = 0
if hasSpikyHair { finalHeight = currentHeight + 5} 
 else { finalHeight = currentHeight }

Too long. Let’s cut the fat.

// Lovely Code
finalHeight = currentHeight + (hasSpikyHair ? 5: 0)

The code above states, if hasSpikeHair is true, add 5 to the final height, if not add zero.