Cutting the mustard

cuttingthemustard.js

// Feature detection
var supports = !!document.querySelector && !!window.addEventListener;
if ( !supports ) return;

// Enabling / hiding content on document load
document.documentElement.className += ' js-component-name';

// Shallow extend
// If a key has another object as its value, the first object's value will be overridden by the second one during the merge.
var extend = function ( objects ) {
    var extended = {};
    var merge = function (obj) {
        for (var prop in obj) {
            if (Object.prototype.hasOwnProperty.call(obj, prop)) {
                extended[prop] = obj[prop];
            }
        }
    };
    merge(arguments[0]);
    for (var i = 1; i < arguments.length; i++) {
        var obj = arguments[i];
        merge(obj);
    }
    return extended;
};

// Deep extend
// If a key has another object as its value, the first object's value will be combined with the second one during the merge.
var deepExtend = function ( objects ) {
    var extended = {};
    var merge = function (obj) {
        for (var prop in obj) {
            if (Object.prototype.hasOwnProperty.call(obj, prop)) {
                if ( Object.prototype.toString.call(obj[prop]) === '[object Object]' ) {
                    extended[prop] = deepExtend(extended[prop], obj[prop]);
                }
                else {
                    extended[prop] = obj[prop];
                }
            }
        }
    };
    merge(arguments[0]);
    for (var i = 1; i < arguments.length; i++) {
        var obj = arguments[i];
        merge(obj);
    }
    return extended;
};

References:
http://responsivenews.co.uk/post/18948466399/cutting-the-mustard
http://gomakethings.com/ditching-jquery/