Spun off from widget-functions this is a big time saver when building DOM in Y.Widget

widget-node-builder.js

YUI.add("widget-node-builder", function (Y) {
  
  /**
   * Extension enabling a Widget to easily build DOM.
   *
   * @module widget-node-builder
   */

  var yNodeCreate     = Y.Node.create,
      yObjectEach     = Y.Object.each,
      yLangIsFunction = Y.Lang.isFunction;

  function nodeSetAttrs(value, key) {
    this.setAttribute(key, value);
  }

  /**
   * Widget extension providing functionality enabling a Widget to build 
   * internal DOM.
   *
   * @class WidgetNodeBuilder
   * @constructor
   * @uses Node
   */
  function WidgetNodeBuilder() {}
  
  /**
   * @method buildNode
   * @param config {Object} An configuration object defining the node. Valid options:
   * <ul>
   *   <li><b>template</b>: The DOM element to create. Defaults to <code>"<div></div>"</code>.</li>
   *   <li><b>className</b>: A value for the <code>class</code> attribute. Uses the host's
   *     <code>getClassName</code> method if available.</li>
   *   <li><b>attrs</b>: An object dictionary of attributes to add to the node
   *      using <code>setAttribute</code>.</li>
   *   <li><b>content</b>: Content to add to the node using <code>setContent</code>.</li>
   * </ul>
   * @description Creates a Node with the provided configuration options.
   * @return {Node} Y.Node wrapping the created DOM.
   */
  WidgetNodeBuilder.prototype.buildNode = function (config) {
    var cfg = config || {},
        node = yNodeCreate(cfg.template || "<div></div>");
    
    if (cfg.className) {
      node.addClass(yLangIsFunction(this.getClassName) ? this.getClassName(cfg.className) : cfg.className);
    }
    if (cfg.attrs) {
      yObjectEach(cfg.attrs, nodeSetAttrs, node);
    }
    if (cfg.content) {
      node.setContent(cfg.content);
    }
    return node;
  };
  
  Y.WidgetNodeBuilder = WidgetNodeBuilder;
  
}, "3.4.1", { requires: ["node-base"] });