Check If Not A Number Javascript Code Example

Example 1: javascript check if number

//Updated dec 2020 // The first 2 Variations return a Boolean // They just work the opposite way around  // IsInteger if (Number.isInteger(val)) { 	// It is indeed a number }  // isNaN (is not a number) if (isNaN(val)) { 	// It is not a number }  // Another option is typeof which return a string if (typeof(val) === 'number') { 	// Guess what, it's a bloody number! }

Example 2: javascript check if number

function isNumber(n) { return /^-?[\d.]+(?:e-?\d+)?$/.test(n); }   ------------------------  isNumber('123'); // true   isNumber('123abc'); // false   isNumber(5); // true   isNumber('q345'); // false isNumber(null); // false isNumber(undefined); // false isNumber(false); // false isNumber('   '); // false

Example 3: To check if a value is a number in JavaScript

const value = 2 isNaN(value) //false isNaN('test') //true isNaN({}) //true isNaN(1.2) //false