A ridiculously small directive compiler

compiler.js

/**
 * compile - compile a set of directive against a piece of DOM
 *
 * @param {Object} directives - the object containing all the directives to compile 
 * against the rootElement. The keys of the object are the css selectors 
 * to retrieve the element in the DOM and the values are the function that 
 * are applied to each element found :
 *  {
 *      "<cssSelector>": function (element) {
 *          //init element here
 *      }
 *  }
 *
 * @param {HTMLElement|undefined} rootElement - the root element of the compilation
 * @return {void} undefined
 */
var compile = function (directives, rootElement) {
    rootElement = rootElement || document;
    for (var i in directives) {
        var elements = rootElement.querySelectorAll(i);
        for (var j = 0; j < elements.length; j++) {
            directives[i](elements[j]);
        }
    }
};