React addon for easier React.DOM building without JSX

React.addons.tagHelper.js

//
//  React addon for easier React.DOM building without JSX
//
//  Usage:
//
//  render: function () {
//    return React.addons.tagHelper(
//      ['#main.container',
//        ['h1', 'Hello!'],
//        ['a.andClass.andAnother', { href: '/' }, 'Home']]
//    );
//  }
//
//
React.addons.tagHelper = (function () {
  'use strict';

  function parseSpec(specString) {
    if (!parseSpec.cache[specString]) {
      var spec = specString.match(parseSpec.matcher);
      parseSpec.cache[specString] = {
        tag: spec[1] || 'div',
        id: spec[3],
        className: (spec[4] || '').replace(/\./gim, ' ').substr(1)
      };
    }
    return parseSpec.cache[specString];
  }
  parseSpec.matcher = /([^#\.]+)?(#([^#\.]+))?((\.[^#\.]+)+)?/;
  parseSpec.cache = {};

  function buildTag(tag, props, children) {
    children.unshift(props);
    return React.DOM[tag].apply(React.DOM, children);
  }

  function mergeSpecToProps(spec, props) {
    if (props.className && props.className.constructor === Object) {
      props.className = React.addons.classSet(props.className);
    }

    if (spec.className) {
      props.className = spec.className + (props.className ? ' ' + props.className : '');
    }

    props.id = props.id || spec.id;
  }

  function getChildren(arr, offset) {
    var children = Array(arr.length - offset);
    for (var i = offset; i < arr.length; i++) {
      var child = arr[i];
      if (child && child.constructor === Array && typeof child[0] === 'string') {
        child = React.addons.tagHelper(child);
      }
      children[i - offset] = child;
    }
    return children;
  }

  return function (params) {
      var childrenOffset = 1;

      var spec = parseSpec(params[0]);

      var props = {};

      if (params[1] && params[1].constructor === Object) {
        props = params[1];
        childrenOffset = 2;
      }

      mergeSpecToProps(spec, props);

      var children = getChildren(params, childrenOffset);

      return buildTag(spec.tag, props, children);
  };
})();