Check if a string is a hexadecimal number

JavaScript

const isHexadecimal = (str) => /^[A-F0-9]+$/i.test(str)

// Or
const isHexadecimal = (str) => str.split('').every((c) => '0123456789ABCDEFabcdef'.indexOf(c) !== -1)

TypeScript

const isHexadecimal = (str: string): boolean => /^[A-F0-9]+$/i.test(str)

// Or
const isHexadecimal = (str: string): boolean => str.split('').every((c) => '0123456789ABCDEFabcdef'.indexOf(c) !== -1)

Examples

isHexadecimal('123') // true
isHexadecimal('A1B2C3') // true
isHexadecimal('#123') // false