why is react-rails not attaching onClick event action to a button?

Question

I'm using react-rails gem to add react components into my rails app. This is a code sample:

let b = <button type="button" onClick={this.onClick} id="678">Click me</button>;
const element = React.createElement(
  'button',
  {
    type: 'button',
    onClick: this.onClick
  },
  'Hello, world!'
);

the onClick event action is not being attached to the button, this is the button object props when I log it :

props : children : "Click me" id : "678" type : "button"