Javascript - Insert variable as Object keys?

Question

I read and tries everything, but I can't figure out how to do this simple thing.

Basically,

var obj = {
    price: 15
};
var foo = "price";

if(obj.[foo] == 15){
    return true;
}

Answer 1

You can use bracket notations. But you're also not doing that correctly.

Let's say you had var foo = 'price'; "price" is a key in obj but not its own variable, so you can't just say var foo = price; (an unset variable).

For bracket notation:

if(obj[foo] == 15){
    return true;
} 

In this case you'd be saying "check to see if the price property of object foo is 15."