Pass props from template into react.js root node

There is a alternative way to achieve this by using data attributes in html. Here's a small example: In html, you add as much properties with the data prefix as you want:

<div id="root" data-prop-one="Property one" data-prop-two="Property two"/>

All data properties will be automatically converted to CamelCased properties in the element's dataset property. Pass this property to your React component and you're done:

let element = document.getElementById('root')
ReactDOM.render(<App myPropsObject={element.dataset}/>, element)

There's nothing in the API to transfer properties from a plain DOM element to a React component, but you could create a Mixin to do it. Note that this will only work on a component passed to renderComponent because it uses setProps:

(Working JSFiddle)

var InheritsDomAttributes = {
  componentDidMount: function(rootNode) {
    var hasNextProps = false;
    var nextProps = {};
    var parentNode = rootNode.parentNode;

    Object.keys(parentNode.attributes).forEach(function(key) {
      var namedNode;

      // NamedNodeMaps have an attribute named "length" that
      // should not be considered a set attribute.
      if (key !== "length") {
        hasNextProps = true;
        namedNode = parentNode.attributes[key];
        nextProps[namedNode.name] = namedNode.value;
      }
    });

    if (hasNextProps) this.setProps(nextProps);
  }
};

var Swoosh = React.createClass({
  mixins: [InheritsDomAttributes],
  render: function() {
    return (
      <div className="swoosh">
        Boom.
      </div>
    );
  }
});

React.renderComponent(
  <Swoosh />,
  document.getElementById('content')
);

No, though of course you can do:

var container = document.getElementById('content');
React.renderComponent(
  <Swoosh
    foo={container.getAttribute('foo')}
    bar={container.getAttribute('bar')}
    bav={container.getAttribute('bav')} />,
  container
);

(or if you want to make an attributes dict using something like https://stackoverflow.com/a/5282801/49485, then you can do Swoosh(attributes)).