Why does a number inside parentheses have methods, but a number outside parentheses does not?

Asked Mar 20 '17 at 18:05

Active Mar 20 '17 at 18:05

Viewed 26 times

In the JavaScript console, if I execute:

2.toString()

I get the error:

Uncaught SyntaxError: Invalid or unexpected token

But if I execute (2).toString(), the result is "2".

Why do I have to use the parentheses in order to apply methods from the Number prototype?

Other "primitives" work without parentheses. For example:

true.toString() => "true"

"".toString() => ""

It doesn't work for null or undefined, of course, since by definition they don't have any properties or methods.

Why is Number different from Boolean and String in this way?

asked Mar 20 '17 at 18:05

Isaac Lyman

1

I bet on parser ambiguity. Dot in `2.toString()` is treated as decimal separator, but is not followed by a digit. Hence the error. – Sergio Tulentsev Mar 20 '17 at 18:07
@MarkReed You're right--thanks, my initial search didn't turn up that question. – Isaac Lyman Mar 20 '17 at 18:09

0 Answers0