[removed] What are .extend and .prototype used for?

Question

I am relatively new to JavaScript and keep seeing .extend and .prototype in third party libraries I am using. I thought it had to do with the Prototype javascript library, b

Answer 1

Some extend functions in third party libraries are more complex than others. Knockout.js for instance contains a minimally simple one that doesn't have some of the checks that jQuery's does:

function extend(target, source) {
    if (source) {
        for(var prop in source) {
            if(source.hasOwnProperty(prop)) {
                target[prop] = source[prop];
            }
        }
    }
    return target;
}