Add onUpdate events to easy cursor

Current edit-course.jsx

  render():ReactElement {
    var cid = this.getParams().cid
    var config = this.config()
    this.saveCourse(this.course().value) // We shouldn't do this on render. It also saves on window resize.

    return (
      <Layout cursor={this.cursor()} config={config} mode={EDIT}>
        <EditOptions cid={cid}/>
      </Layout>
    )
  }
  
  saveCourse(course:Course):void {
    ...
  }  
  

New edit-course.jsx

componentDidMount() {
  this.cursor().onUpdate(this.saveCourse)
}  

// onUpdate handler gets passed the current cursor value, in this case the course
saveCourse(course:Course):void {
    ...
} 

Yeah, I like this idea. Any idea how much it would take to implement?