This is a ReactJS code snippet that we used for our blog post https://rubygarage.org/blog/react-vs-angularjs at RubyGarage. It demonstrates how we compose a JS program from functions in ReactJS. This code snippet was taken from a well-known TodoMVC application.

creation_of_a_class_for_todoapp_in_react.js

var TodoApp = React.createClass({
  getInitialState: function () {
    return {
      nowShowing: app.ALL_TODOS,
      editing: null,
      newTodo: ''
    };
  },
  handleChange: function (event) {
    this.setState({
      newTodo: event.target.value
    });
  }
});
// other code is omitted for brevity