Swift and JavaScript comparison snippets

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Table of content

• The Basics
• Basic Operators
• Strings and Characters
• Collection Types
• Control Flow
• Functions
• Closures
• Classes
• Inheritance

The Basics

Constants and Variables

Swift

// declare a constant 
let maximumNumberOfLoginAttempts = 10

// declare a variable
var currentLoginAttempt = 0

// declare multiple constants or multiple variables on a single line, separated by commas
var x = 0.0, y = 0.0, z = 0.0

JavaScript

// declare a constant 
const maximumNumberOfLoginAttempts = 10

// declare a variable
var currentLoginAttempt = 0 
// or 
let currentLoginAttempt = 0

// declare multiple constants or multiple variables on a single line, separated by commas
var x = 0.0, y = 0.0, z = 0.0

Comments

Swift

// This is a comment.

/* This is also a comment
but is written over multiple lines. */

JavaScript

// This is a comment.

/* This is also a comment
but is written over multiple lines. */

Numeric Type Conversion

Swift

let pi = 3.14159
// Integer and Floating-Point Conversion
let integerPi = Int(pi)

JavaScript

const pi = 3.14159
// Integer and Floating-Point Conversion
const integerPi = parseInt(pi)

Booleans

Swift

let orangesAreOrange = true
let turnipsAreDelicious = false

if turnipsAreDelicious {
    print("Mmm, tasty turnips!")
} else {
    print("Eww, turnips are horrible.")
}

JavaScript

const orangesAreOrange = true
const turnipsAreDelicious = false

if (turnipsAreDelicious) {
    console.log("Mmm, tasty turnips!")
} else {
    console.log("Eww, turnips are horrible.")
}

Error Handling

Swift

func canThrowAnError() throws {
    // this function may or may not throw an error
}
do {
    try canThrowAnError()
    // no error was thrown
} catch {
    // an error was thrown
}

JavaScript

function canThrowAnError() {
    // this function may or may not throw an error
}
try {
    canThrowAnError()
    // no error was thrown
} catch (e) {
    // an error was thrown
}