data binding in react + signalR

Question

I have a strategy question.

I want to change data in my website using signalR and display changed data using react. My question would be: How to perform data binding between signalR and react?

My first clue is the following:

signalR:

chat.client.addMessage = function (name, message) {
    chatHistory.push({ Author: name, Text: message }); //here I change global variable chatHistory
};

react:

var CommentList = React.createClass({some class here});

var CommentBox = React.createClass({
    componentRefresh: function () {
        this.setState({ data: chatHistory });
    },
    getInitialState: function () {
        return { data: chatHistory };
    },
    componentDidMount: function () {
        this.componentRefresh();
        setInterval(this.componentRefresh, this.props.interval);
    },
    render: function () {
        return (
          React.DOM.div(null,
            CommentList({ data: this.state.data })
          )
      );
    }
});

React.renderComponent(
  CommentBox({ interval: 2000 }),
  document.getElementById('content')
);

in react commentBox component I feed global chatHistory and ask for a new value every 2 seconds.

Is there more elegant way of doing it? and how to avoid redrawing of CommentBox if chatHistory variable wasn't changed?

Answer 1

Your approach of maintaining state in CommentBox is fine. As your component base grows, it might become complicated to maintain self-updating components though. I recommend investigating the Flux architecture the React team designed and their Todo MVC Flux example in particular.

You could implement shouldComponentUpdate to prevent React from re-rendering the CommentBox if you know state hasn't changed. Also, you should keep a reference to the interval so you can clear it when the CommentBox is unmounted otherwise it will go on polling after the component is removed.

var CommentBox = React.createClass({
  ...

  componentDidMount: function() {
    this.componentRefresh();
    this._interval = setInterval(this.componentRefresh, this.props.interval);
  },

  componentWillUnmount: function() {
    clearInterval(this._interval);
    this._interval = null;
  },

  shouldComponentUpdate: function(nextProps, nextState) {
    // Do a deep comparison of `chatHistory`. For example, use
    // Underscore's `isEqual` function.
    return !_.isEqual(this.state.chatHistory, nextState.chatHistory);
  },

  ...
});