Check if a number is even

JavaScript

const isEven = (n) => n % 2 === 0

// Or
const isEven = (n) => (n & 1) === 0

// Or
const isEven = (n) => !(n & 1)

// Or
const isEven = (n) => Number.isInteger(n / 2)

TypeScript

const isEven = (n: number): boolean => n % 2 === 0

// Or
const isEven = (n: number): boolean => (n & 1) === 0

// Or
const isEven = (n: number): boolean => !(n & 1)

// Or
const isEven = (n: number): boolean => Number.isInteger(n / 2)

Examples

isEven(1) // false
isEven(2) // true