How do I check for undefined values in IE8?

Question

I have this in my javascript:

console.log(filters);
console.log('----');
console.log(filters.max_price);

In Chrome, it shows this. This is the expected behavior.

Object {max_price: undefined, sort_by: undefined, distance: undefined, start: undefined, num: undefined}
----
undefined 

In IE8, the log shows this:

LOG: Object Object
----
LOG: String

Why does IE8 think it is a string? I need to know if it's undefined.

I have lots of code that sets default values.

if(typeof filters.max_price == undefined){ //I use this technique a lot! 
    filter.max_price = 2000; 
}

How can I check for undefine-ds in IE8? Should I do this? This seems to work (yay...), but it seems cheap and hacky.

if(!filters.max_price || typeof filters.max_price == 'undefined'){

Is there a simple way I can do this with underscore?

Answer 1

You can use this approach, but it would not reduce your code a lot:

filters.max_price = filters.max_price || 2000;

This, however, would overwrite the value if it's 0. The best approach remains:

if(typeof filters.max_price === 'undefined'){
    // init default
}