Question

I am new to constructor functions, and I have the following in a .js file I include:

// should just get the number of customers out of the passed-in object
function myCustomers(customerObj) {
    this.customerCount = function(customerObj) {
        return customerObj.length;
    };
}

On the .htm page which includes the .js file, I have the following:

var tmpObj = new myCustomers(custObj);
alert(tmpObj.customerCount);

What I expected was the alert to give me the number of customers, such as “1”, etc. Instead, the alert contains the entire text of my function as though it were a string, like this:

function(customerObj) {
    return customerObj.length;
}

I’m sure this is simple, but I have had a tough time googling for an answer, since my search contains very generic words like function, text/string, method, etc. FYI, this example has been pared down from a more complicated function, to hopefully make it easier to understand the question. I have tested this simpler function with the same result.

Thanks in advance!

Answer 1

It looks like in your alert, you are not actually calling the function, but instead passing the function itself to alert(). Try this:

alert(tmpObj.customerCount(custObj));

You might also want to change your myCustomers object to hang on to the object that is passed into the constructor, so you don’t have to pass it in again when you call the function.