Javascript: How to check string type?

Question

So I would like to know what's inside the string for example:

var str = "a"; // Letter
var str = "1"; // Number
var str = "["; // Special
var str = "@"; // Special
var str = "+"; // Special

Is there any pre defined javascript function for this? Otherwise I will make it with regex :)

You might want to check this question: http://stackoverflow.com/questions/18082/validate-numbers-in-javascript-isnumeric before delving into Regular Expressions for numeric validation — Dancrumb, Dec 11 '10 at 18:29
I don't think CIRK is wanting to do actual numeric validation, rather just determine the type of a single character. Certainly, that's the impression I get from the examples in their post. — El Ronnoco, Dec 11 '10 at 19:06

El Ronnoco · Accepted Answer · 2010-12-11T18:45:50.563

3

if (/^[a-zA-Z]$/.test(str)){
    // letter
} else if (/^[0-9]$/.test(str)){
    // number
} else {
    // other
};

Of course this only matches one character so 'AA' would end up in the //other section.

edited Dec 11 '10 at 18:45

answered Dec 11 '10 at 18:28

El Ronnoco

score 2 · Answer 2 · answered Dec 11 '10 at 18:25

2

They are all strings...

There isn't anything built in that will do what you want.

A regex may be a good solution, though you have not really provided enough information for one.

answered Dec 11 '10 at 18:25

Oded

@Joel Coehoorn - Some people, when confronted with a problem, think “I know, I'll use regular expressions.” Now they have two problems. ;) – Oded Dec 11 '10 at 18:27

score 0 · Answer 3 · edited Aug 18 '12 at 16:07

0

if(isNaN(string)){
   //yes is a string
}

edited Aug 18 '12 at 16:07

Conner

answered Dec 11 '10 at 18:56

mavirroco

3 Answers3