Integer changes to String

[LuckyKoen]

I have some experience in Java but I am new to JavaScript. What confuses me is that you don't have to declare the type of a variable when defining it. Here is an example of how this is sometimes hard for me to work with :

function getInt(anInteger) {
	if (anInteger == 10) {
		return anInteger + 5;
	}
	else {
		return anInteger - 5;
	}
}

getInt(10) returns 105
getInt(15) returns 10

Is there a clean way to make sure that anInteger + 5 returns 15 and not 105 ? I use anInteger - 0 + 5 now, but I'd like to know if there is a better way to do it.

 

[BillyRayPreachersSon]

You can use parseInt to ensure a number is always treated as such:

var someNum = parseInt(someOtherNum, 10);

The ", 10" tells JS to use decimal (base 10).

Hope this helps,
Dan


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[BabyJeffy]

A shorthand technique that I use from time to time forces a string into a number... by subtracting zero the result is cast as a number... so the next operation (a + operation) is then treated as addition rather than concatenation:

function getInt(anInteger) {
    if (anInteger == 10) {
        return (anInteger - 0) + 5;
    }
    else {
        return anInteger - 5;
    }
}

Of course, parseInt() would do the same (as Dan mentioned above).
Cheers,
Jeff

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