Concatenating the values of an object's properties returns NaN (Javascript)

Question

I have an object with multiple properties, each property has a value that is a string. When I try to concatenate the values of each property, it returns NaN.

var urlProps = {
   searchTerm: "searchSTUFF",
   baseURL: "https://en.wikipedia.org/w/api.php?action=query&prop=extracts&format=json&exsentences=1&exlimit=10&exintro=&explaintext=&titles=%20&generator=search&gsrsearch=",
   tailURL: "&rawcontinue=&callback=?",
   finalURL: this.baseURL + this.searchTerm + this.tailURL
}

console.log(urlProps.finalURL);
//NaN

What am I doing wrong here, or what is the proper way of doing this?

Answer 1

At the point where you're trying to concatenate the values the object has not yet been created.
Also this would not represent the object in any case. You'd use this in a constructor or an object method.
To get the result you want you'll have to do this.

var urlProps = {
   searchTerm: "searchSTUFF",
   baseURL: "https://en.wikipedia.org/w/api.php?action=query&prop=extracts&format=json&exsentences=1&exlimit=10&exintro=&explaintext=&titles=%20&generator=search&gsrsearch=",
   tailURL: "&rawcontinue=&callback=?",
   finalURL: this.baseURL + this.searchTerm + this.tailURL
}
urlProps.finalURL = urlProps.baseURL + urlProps.searchTerm + urlProps.tailURL;

Answer 2

I would suggest using function

var urlProps = {
   searchTerm: "searchSTUFF",
   baseURL: "https://en.wikipedia.org/w/api.php?action=query&prop=extracts&format=json&exsentences=1&exlimit=10&exintro=&explaintext=&titles=%20&generator=search&gsrsearch=",
   tailURL: "&rawcontinue=&callback=?",
   finalURL: function() { return this.baseURL + this.searchTerm + this.tailURL; }
}

console.log(urlProps.finalURL());
//https://en.wikipedia.org/w/api.php?action=query&prop=extracts&format=json&e…=&titles=%20&generator=search&gsrsearch=searchSTUFF&rawcontinue=&callback=?