Swift and JavaScript comparison snippets(2) — Basic Operators

Assignment Operator

Swift

let b = 10var a = 5a = b

// decomposed tuple with multiple values into multiple variableslet (x, y) = (1, 2)print("x = \(x), y = \(y)") // x = 1, y = 2

JavaScript

let b = 10var a = 5a = b

// object matching with destructuring assignmentconst {x, y} = {x:1, y:2}console.log(`x = ${x}, y = ${y}`) // x = 1, y = 2// or array matching with destructuring assignmentconst [x, y] = [1, 2]console.log(`x = ${x}, y = ${y}`) // x = 1, y = 2

Arithmetic Operators

• Addition (+)
• Subtraction (-)
• Multiplication (*)
• Division (/)

Swift

1 + 2 // equals 35 - 3 // equals 22 * 3 // equals 610.0 / 2.5 // equals 4.0"hello, " + "world" // equals "hello, world"

JavaScript

1 + 2 // equals 35 - 3 // equals 22 * 3 // equals 610.0 / 2.5 // equals 4"hello, " + "world" // equals "hello, world"

Remainder Operator

Swift

9 % 4 // equals 1-9 % 4 // equals -1

JavaScript

9 % 4 // equals 1-9 % 4 // equals -1

Unary Minus/Plus Operator

Swift

let three = 3let minusThree = -three // minusThree equals -3let plusThree = -minusThree // plusThree equals 3, or "minus minus three"

let minusSix = -6let alsoMinusSix = +minusSix // alsoMinusSix equals -6

JavaScript

const three = 3const minusThree = -three // minusThree equals -3const plusThree = -minusThree // plusThree equals 3, or "minus minus three"

const minusSix = -6const alsoMinusSix = +minusSix // alsoMinusSix equals -6

Compound Assignment Operators

Swift

var a = 1a += 2 // a is now equal to 3

JavaScript

let a = 1a += 2 // a is now equal to 3

Comparison Operators

• Equal to (a == b)
• Not equal to (a != b)
• Greater than (a > b)
• Less than (a < b)
• Greater than or equal to (a >= b)
• Less than or equal to (a <= b)
• Identity operators, refer to the same object instance (a === b)
• Identity operators, not refer to the same object instance (a !== b)

Swift

1 == 1 // true because 1 is equal to 12 != 1 // true because 2 is not equal to 12 > 1 // true because 2 is greater than 11 < 2 // true because 1 is less than 21 >= 1 // true because 1 is greater than or equal to 12 <= 1 // false because 2 is not less than or equal to 1

let name = "world"if name == "world" {print("hello, world")} else {print("I'm sorry \(name), but I don't recognize you")}// Prints "hello, world", because name is indeed equal to "world".

let p1 = Person();let p2 = Person();p1 === p2 // falsep1 !== p2 // true

JavaScript

1 == 1 // true because 1 is equal to 12 != 1 // true because 2 is not equal to 12 > 1 // true because 2 is greater than 11 < 2 // true because 1 is less than 21 >= 1 // true because 1 is greater than or equal to 12 <= 1 // false because 2 is not less than or equal to 1

const name = "world"if (name == "world") {console.log("hello, world")} else {console.log(`I'm sorry ${name}, but I don't recognize you`)}// Prints "hello, world", because name is indeed equal to "world".

const p1 = new Person();const p2 = new Person();p1 === p2 // falsep1 !== p2 // true

Ternary Conditional Operator

Swift

let contentHeight = 40let hasHeader = truelet rowHeight = contentHeight + (hasHeader ? 50 : 20)// rowHeight is equal to 90

JavaScript

const contentHeight = 40const hasHeader = trueconst rowHeight = contentHeight + (hasHeader ? 50 : 20)// rowHeight is equal to 90

Logical Operators

• Logical NOT (!a)
• Logical AND (a && b)
• Logical OR (a || b)

Swift

let allowedEntry = falseif !allowedEntry {print("ACCESS DENIED")}// Prints "ACCESS DENIED"

let hasDoorKey = falselet knowsOverridePassword = trueif enteredDoorCode && passedRetinaScan || hasDoorKey || knowsOverridePassword {print("Welcome!")} else {print("ACCESS DENIED")}// Prints "Welcome!"

JavaScript

const allowedEntry = falseif (!allowedEntry) {console.log("ACCESS DENIED")}// Prints "ACCESS DENIED"

const hasDoorKey = falseconst knowsOverridePassword = trueif (enteredDoorCode && passedRetinaScan || hasDoorKey || knowsOverridePassword) {console.log("Welcome!")} else {console.log("ACCESS DENIED")}// Prints "Welcome!"

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