Why JS returns NaN in: ` + 'any_string'`

Question

Why JS returns NaN in: + 'any_string'?

Please check the screenshot:

Answer 1

Using the unary plus operator you can convert something into a number. By doing +'some_string' you convert the string to a number, but since some_string is not a valid number you get NaN Not a Number.

Answer 2

The "+" tries to convert the string to an integer. See docs here

As it has failed to convert it to a number, the output is NaN : Not A Number

console.log(+"3");
console.log(+"randomString");