old_contents: import React from 'react';
  import state from '../../state';
  
  
  // #TODO: remove debug code
  state.getCursor().update({ $set: { a: { b: { c: 1 } } } });
  
  
  export default React.createClass({
  
      mixins: [ state ],
  
      getInitialState() {
          return this.getCursor(['a', 'b']);
      },
  
      handleClick() {
          this.state.update({ c: { $apply: v => v + 1 } });
      },
  
      render() {
          return (
              <section>
                  <input/>
                  <div onClick={ this.handleClick }>
                      click count: { this.state.c }
                  </div>
              </section>
          );
      }
  });
new_contents: import React from 'react';
  import state from '../../state';
  
  
  // #TODO: remove debug code
  state.getCursor().update({ $set: { a: { b: { c: 1 } } } });
  
  
  export default React.createClass({
  
      mixins: [ state ],
  
      keyPath: ['a', 'b'],
  
      handleClick() {
          this.state.update({ c: { $apply: v => v + 1 } });
      },
  
      render() {
          return (
              <section>
                  <input/>
                  <div onClick={ this.handleClick }>
                      click count: { this.state.c }
                  </div>
              </section>
          );
      }
  });
subject: update hello component