Is it possible to use string functions on numbers in javascript?

Question

Can you tell me if it is ok to use string functions on numbers in Javascript? I have a code which needs to do some modifications on string values. Like here:

var value = 0;

if( tableRow.find('input').length )
{
    value = tableRow.find('input').val();
}

value = value.replace(/\s/g, '')  // Remove spaces

But sometimes value before replace() remains default 0 which is number type. So is it ok to call replace( or other string function ) on the number? It seems it works but I am not sure if all browsers will support it.

EDIT: Not it is not possible. My code works fine because it is always string and condition is not skipped. But variables of number type have NOT .string() function.

Have you tried to `console.log( typeof someInput.value )` or `console.log( typeof $somejQInput.val() )` ? — Roko C. Buljan, Jul 25 '18 at 08:34
your code is modifying `String`s, it never modifies `Number`s so there's not a problem — Jaromanda X, Jul 25 '18 at 08:36

score 3 · Answer 1 · edited Aug 27 '18 at 21:00

3

You can't call replace on a number. What you can do is to call it on value.toString() or to set value initially to 0

edited Aug 27 '18 at 21:00

Hyyan Abo Fakher

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answered Jul 25 '18 at 08:34

Programmer

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Yes you are right. Numbers has no .string() function. My code works cause it is always string and conditions is not skipped in my case. – Čamo Jul 25 '18 at 08:37

score 3 · Answer 2 · answered Jul 25 '18 at 08:41

Is it possible to use string functions on numbers in javascript?

No. Numbers and strings have different methods. Numbers don't have a replace method (because it doesn't make sense for numbers, but does make sense for strings).

But sometimes value before replace() remains default 0 which is number type.

To avoid that, make your default a string as well:

var value = "0";
// ---------^-^

if( tableRow.find('input').length )
{
    value = tableRow.find('input').val();
}

value = value.replace(/\s/g, '')  // Remove spaces

...or only do the replace on the other path, and convert to number on the other path:

var value = 0;

if( tableRow.find('input').length )
{
    value = tableRow.find('input').val();
    value = +value.replace(/\s/g, '')  // Remove spaces, convert to number
}

(+ is just one way to convert to number. You have several options, each with pros and cons.)

score 0 · Answer 3 · answered Jul 25 '18 at 08:37

No, it's not possible to use replace on numbers, because there is not such function in the Number class.

Your value propably is a string, (check it with typeof(value) ), that string containing only numbers don't make it a number.

value = 10 it's not the same as value = "10".

Is it possible to use string functions on numbers in javascript?

3 Answers3