What is the shortest way of converting any JavaScript value to a string?

Question

I have a function, say:

setValue: function(myValue) {
  ...
}

The caller might pass a string, number, boolean, or object. I need to ensure that the value passed further down the line is a string. What is the safest way of doing this? I realize there are many ways some types (e.g. Date) could be converted to strings, but I am just looking for something reasonable out of the box.

I could write a series of typeof statements:

if (typeof myValue == "boolean") {}
else if () {}
...

But that can be error-prone as types can be missed.

Firefox seems to support writing things like:

var foo = 10; foo.toString()

But is this going to work with all web browsers? I need to support IE 6 and up.

In short, what is the shortest way of doing the conversion while covering every single type?

-Erik

This subject has already been discussed : stackoverflow.com/questions/869773/… — Fabien Ménager
– Fabien Ménager, Commented May 26, 2009 at 18:13

Darin Dimitrov · Accepted Answer · 2009-05-26 18:08:15Z

9

var stringValue = String(foo);

or even shorter

var stringValue = "" + foo;

answered May 26, 2009 at 18:08

Darin Dimitrov

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Fabien Ménager · Accepted Answer · 2009-05-26 18:08:59Z

3

value += '';

answered May 26, 2009 at 18:08

Fabien Ménager

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patjak · Accepted Answer · 2009-05-26 18:10:03Z

2

If you use myValue as a string, Javascript will implicity convert it to a string. If you need to hint to the Javascript engine that you're dealing with a string (for example, to use the + operator), you can safely use toString in IE6 and up.

answered May 26, 2009 at 18:10

patjak

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Andrey · Accepted Answer · 2009-05-26 18:09:05Z

0

what about forcing string context, e.g. ""+foo?

answered May 26, 2009 at 18:09

Andrey

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Helgi · Accepted Answer · 2009-05-26 20:09:36Z

0

Yet another way is this:

var stringValue = (value).toString();

answered May 26, 2009 at 20:09

Helgi

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