If a property chain exists, access it, else return undefined.

maybe.js

/*! maybe.js | v0.1.0 */
// If a property chain exists, access it, else return undefined.
//
// eg:
// var url = maybe(app, 'config.environment.buildURL', ['dev']);

var maybe = (function () {

    // Different values for normal browser, strict mode, node.js, etc.
    var defaultContext = this;

    return function maybe(obj) {
        var prevObj = defaultContext;
        var nArgs = arguments.length;
        var i = 0;
        var prop = '';
        var arg, tmp;

        for (i = 1; i < nArgs; i += 1) {
            arg = arguments[i];

            if (typeof arg === 'string') {
                arg = arg.split('.');

                while ((prop = arg.shift()) !== undefined) {
                    if (obj instanceof Object && prop in obj) {
                        prevObj = obj;
                        obj = obj[prop];
                    } else {
                        return undefined;
                    }
                }

            } else if (Array.isArray(arg)) {
                if (obj instanceof Function) {
                    tmp = obj.apply(prevObj, arg);
                    prevObj = obj;
                    obj = tmp;
                } else {
                    return undefined;
                }
            } else {
                throw Error('Invalid argument');
            }
        }
        return obj;
    };
})();