# Validate number

Checks if the given value is a number.

- Use
`parseFloat()`

to try to convert`n`

to a number. - Use
`Number.isNaN()`

and logical not (`!`

) operator to check if`num`

is a number. - Use
`Number.isFinite()`

to check if`num`

is finite. - Use
`Number`

and the loose equality operator (`==`

) to check if the coercion holds.

const validateNumber = n => { const num = parseFloat(n); return !Number.isNaN(num) && Number.isFinite(num) && Number(n) == n; } validateNumber('10'); // true validateNumber('a'); // false