JSFiddle - React, Tailwind, and code Playground

HTML

<script src="//code.jquery.com/jquery-1.9.1.min.js"></script>

JavaScript

function myFunc( args ) {
    var defaults = {
        optionalA: 'Some default',
        optionalB: 'I am a default value',
        optionalC: 'Some other default'
    };
    args = $.extend({}, defaults, args);
    alert(args.optionalA+" - "+args.optionalB);
}

// example using it
myFunc({
    optionalA: "This is not a default! WTF",
    optionalC: "I'm not a default neither!"
});