30-seconds-of-code/snippets/isNumber.md

title, tags, firstSeen, lastUpdated

title	tags	firstSeen	lastUpdated
isNumber	type,math,beginner	2017-12-17T17:55:51+02:00	2020-09-15T16:28:04+03:00

Checks if the given argument is a number.

• Use typeof to check if a value is classified as a number primitive.
• To safeguard against NaN, check if val === val (as NaN has a typeof equal to number and is the only value not equal to itself).

const isNumber = val => typeof val === 'number' && val === val;

isNumber(1); // true
isNumber('1'); // false
isNumber(NaN); // false