JEST throws .finally is not a function

user_4975172 0
Viewed 5454

Here is my react component:

import { sendAnalytics } from 'analytics';

class MyComponent extends React.Component {
    myMethod() {
        console.log('do something!');
    }

    render() {
        return (
            <Button 
                onClick={submitAnalytics({name: 'foo'}).finally(this.myMethod())} 
                dataset={{"data-id": "button"}}
            > Send Analytics
            </Button>
            }
        )
    }
}

And my test is like so:

import * as analytics from 'analytics';
jest.mock('analytics');

describe('Analytics', () => {
    it('Should call analytics when button is clicked', () => {
        analytics.submitAnalytics.mockResolvedValue(Promise.resolve(true));
        const tree = ReactTestRenderer.create(<MyComponent />);

        // Actual implementation of following 3 lines is slightly different.
        const button = tree.root.findByProps({"data-id": "button"});
        button.props.onClick();
        expect(analytics.submitAnalytics).toHaveBeenCalled();
    });
});

I tried several different mocking strategies like:

analytics.submitAnalytics.mockImplementation(() => {
    return Promise.resolve(true)
});

Nothing seems to work out. I keep getting the following error:

TypeError: (0 , analytics.submitAnalytics)(...).finally is not a function.

I don't know why. Any help appreciated. Please let me know if you need any more contextual code.

jestjs reactjs javascript
5 Answers

Importing @babel/polyfill before the test also solve this problem

import '@babel/polyfill';

// Your tests...
user_54448530

Upgrading my node version from

v8.10.0

to

v10.19.0

Resolved this error.

Looking at the Browser Compatibility chart on MDN it looks like .finally() is not supported in Node until 10.0.0

user_74752500

import '@babel/polyfill'; worked for me, but is deprecated since babel 7.4.

Instead, import this works fine as well:

import "core-js/stable";
import "regenerator-runtime/runtime";

eventually, I just updated node version (from 8.10.2 to 12.16.1)

user_122268010

I figured it out folks! Here's what was to be done:

analytics.submitPayload = jest.fn().mockImplementation(() => {
  return {
    finally: () => {
      return true;
    }
  };
});

I don't know if this is right or wrong, but it works. Please let me know if there's a better way to do it.

user_49751720
user_53088690
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