Check function name in Javascript

Question

Here is my code:

object = {'name' : String}
object = {'age' : Number}
typeof object.name // 'function'
typeof object.age // 'function'

Is it possible to check that object.name is a String and object.age is a Number?

Using typeof only gives me back 'function'.

You realize String is the actual string constructor, right? If that's what you want to check, you can just do object.name == String. — Matthew Flaschen
– Matthew Flaschen, Commented Nov 11, 2010 at 8:17
i think you might be thinking in Actionscript. In Javascript, the rhs of the property is the value or instance of an object, not a type. eg var object = { name: 'geoff', age: 66 }; — user69820
– user69820, Commented Nov 11, 2010 at 8:21
At this point, you might want to look into Microsoft's TypeScript now that's it been released. — jdotjdot
– jdotjdot, Commented Oct 7, 2012 at 2:08

Sarfraz · Accepted Answer · 2010-11-11 08:32:31Z

4

Rather than doing:

object = {'name' : String}
object = {'age' : Number}

You should check for actual data type:

object = {'name' : 'test', 'age' : 123}

And here is how you can check their type:

alert(typeof(object.name));
alert(typeof(object.age));

Output:

string
number

edited Nov 11, 2010 at 8:32

answered Nov 11, 2010 at 8:26

Sarfraz

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Halil Özgür · Accepted Answer · 2010-11-11 08:42:50Z

0

var object = {
    "name" : "test",
    "age"  : 123
};

if (!isNaN(parseInt(object.age, 10))) {
    // It is a numerical value (since this is an age, an int may be appropriate)
    alert("It's numeric!");
}
if (object.name.toString() === object.name) {
    // It is really a string
    alert("It's a string!");
}

answered Nov 11, 2010 at 8:42

Halil Özgür

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