Something like this?

 useEffect(() => {
    const cancelTokenSource = axios.CancelToken.source();

    const fetchData = async () => {
      dispatch({ type: 'FETCH_INIT' });

      try {
        const result = await await axios(url, {
            cancelToken: cancelTokenSource.token,
          });

        if (!axios.isCancel()) {
          dispatch({ type: 'FETCH_SUCCESS', payload: result.data });
        }
      } catch (error) {
        if (!axios.isCancel(error)) {
          dispatch({ type: 'FETCH_FAILURE' });
        }
      }
    };

    fetchData();

    return () => {
      cancelTokenSource.cancel();
    };
  }, [url]);

Thanks for your blog post on data fetching with React Hooks. I'm learning React Hooks and found it helpful.

Dan Abramov recently released a react-hooks/exhaustive-deps eslint rule. So I added eslint-plugin-react-hooks to a fork of this repo and got the following errors:

$ npm run -s eslint

/opt/gh/react-hooks-introduction/src/customHook-example/index.js
  22:6  warning  React Hook useEffect has missing dependencies: 'onOffline' and 'onOnline'. Either include them or remove the dependency array  react-hooks/exhaustive-deps

/opt/gh/react-hooks-introduction/src/useDataApiHook-example/index.js
  29:5  warning  React Hook useEffect has a missing dependency: 'fetchData'. Either include it or remove the dependency array  react-hooks/exhaustive-deps

✖ 2 problems (0 errors, 2 warnings)
  0 errors and 2 warnings potentially fixable with the `--fix` option.

I have come up with solutions in my own code, but am curious how others such as yourself would solve them.

The dependency use-data-api was updated from 1.0.0 to 1.0.1.

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The dependency react-scripts was updated from 3.0.0 to 3.0.1.

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There have been updates to the react monorepo:

• • The dependency react was updated from 16.7.0-alpha.2 to 16.7.0.

• The dependency react-dom was updated from 16.7.0-alpha.2 to 16.7.0.

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