JavaScript Patterns 6.6 Mix-ins

Loop through arguments and copy every property of every object passed to the function. And the result will be a new object that has the properties of all the source objects.

function mix() {
 
    var arg, prop, child = {};
 
    for (arg = 0; arg < arguments.length; arg += 1) {
 
        for (prop in arguments[arg]) {
 
            if (arguments[arg].hasOwnProperty(prop)) {
 
                child[prop] = arguments[arg][prop];
 
            }
 
        }
 
    }
 
    return child;
 
}
 
var cake = mix({
 
    eggs: 2,
 
    large: true
 
}, {
 
    butter: 1,
 
    salted: true
 
}, {
 
    flour: "3 cups"
 
}, {
 
    sugar: "sure!"
 
});
 
console.dir(cake);

References: 

JavaScript Patterns - by Stoyan Stefanov (O`Reilly)