Constants and Variables Swift // declare a constantlet maximumNumberOfLoginAttempts = 10 // declare a variablevar currentLoginAttempt = 0 // declare multiple constants or multiple variables on a single line, separated by commasvar x = 0.0, y = 0.0, z = 0.0 JavaScript // declare a constantconst maximumNumberOfLoginAttempts = 10 // declare a variablevar currentLoginAttempt = 0// orlet currentLoginAttempt = 0 // declare multiple constants or multiple variables on a single line, separated by commasvar x = 0.0, y = 0.0, z = 0.0 Comments Swift // This is a comment. /* This is also a commentbut is written over multiple lines. */ JavaScript // This is a comment. /* This is also a commentbut is written over multiple lines. */ Numeric Type Conversion Swift let pi = 3.14159// Integer and Floating-Point Conversionlet integerPi = Int(pi) JavaScript const pi = 3.14159// Integer and Floating-Point Conversionconst integerPi = parseInt(pi) Booleans Swift let orangesAreOrange = truelet turnipsAreDelicious = false if turnipsAreDelicious {print("Mmm, tasty turnips!")} else {print("Eww, turnips are horrible.")} JavaScript const orangesAreOrange = trueconst 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} More of Swift and JavaScript comparison snippets
