lodash/support.js

define(['./internal/root'], function(root) {

  /** Used to detect DOM support. */
  var document = (document = root.window) ? document.document : null;

  /**
   * An object environment feature flags.
   *
   * @static
   * @memberOf _
   * @type Object
   */
  var support = {};

  (function(x) {
    var Ctor = function() { this.x = x; },
        object = { '0': x, 'length': x },
        props = [];

    Ctor.prototype = { 'valueOf': x, 'y': x };
    for (var key in new Ctor) { props.push(key); }

    /**
     * Detect if the DOM is supported.
     *
     * @memberOf _.support
     * @type boolean
     */
    try {
      support.dom = document.createDocumentFragment().nodeType === 11;
    } catch(e) {
      support.dom = false;
    }
  }(1, 0));

  return support;
});