MyComponent3.tsx

@inject("userStore")
@withRouter
@observer
class MyComponent extends React.Component<MyComponentProps, {}> {
  get injected() {
    return this.props as InjectedProps;
  }

  render() {
    const { name, countryCode } = this.props;
    const { userStore, router } = this.injected;
    ...
  }
}