spy on component method failed

[tpai]

I'm now using class properties feature on component method, but the spy seems not work.

The component like this:

// Sample.js
export default class Sample extends Component {
  sampleMethod = () => {
    console.log("sample");
  }
  render() {
    return (<button onClick={this.sampleMethod}>Sample</button>);
  }
}

Test code here:

// Sample.test.js
import { mount } from "enzyme";
import expect from "expect";
import Sample from "./Sample.js";

const wrapper = mount(<Sample />);
const spy = expect.spyOn(wrapper.instance(), "sampleMethod");
expect(spy).toNotHaveBeenCalled();
wrapper.find("#sample").simulate("click");
expect(spy).toHaveBeenCalled();

The result is spy was not called, is that class properties issue or just I wrote wrongly?

[ljharb]

@Geczy yes, it absolutely is, and has always done so with its use of arrow functions in class fields.

The babel transform exists because the spec allows for functions in fields (because it'd be weird for it not to permit it) and the transform has to follow the spec. That's utterly irrelevant to whether you should use certain patterns.