📓 4.5.0.6 NY Times API: Implementing useReducer

Now it's time to refactor the TopStories component to use the useReducer() hook. Let's first take a look at the updated code, and then review the changes in detail down below.

If you want to take on a challenge, try refactoring the TopStories component to use the useReducer() hook by yourself before looking at the updated code below.

src/components/TopStories.js

// We remove the useState hook and add the useReducer hook.
import React, { useEffect, useReducer } from 'react';
import topStoriesReducer from './../reducers/top-stories-reducer';
// We import our action creators.
import { getTopStoriesFailure, getTopStoriesSuccess } from './../actions/index';

// We create initial state for the useReducer hook.
const initialState = {
  isLoaded: false,
  topStories: [],
  error: null
};

function TopStories () {
  // We initialize the useReducer hook.
  const [state, dispatch] = useReducer(topStoriesReducer, initialState);

  useEffect(() => {
    fetch(`https://api.nytimes.com/svc/topstories/v2/home.json?api-key=${process.env.REACT_APP_API_KEY}`)
      .then(response => {
        if (!response.ok) {
          throw new Error(`${response.status}: ${response.statusText}`);
        } else {
          return response.json()
        }
      })
      .then((jsonifiedResponse) => {
        // We create an action and then dispatch it.
        const action = getTopStoriesSuccess(jsonifiedResponse.results)
        dispatch(action);
      })
      .catch((error) => {
        // We create an action and then dispatch it. 
        const action = getTopStoriesFailure(error.message)
        dispatch(action);
      });
    }, [])
  
  // we destructure error, isLoaded, and topStories from the state variable.
  const { error, isLoaded, topStories } = state;

  if (error) {
    return <h1>Error: {error}</h1>;
  } else if (!isLoaded) {
    return <h1>...Loading...</h1>;
  } else {
    return (
      <React.Fragment>
        <h1>Top Stories</h1>
        <ul>
          {topStories.map((article, index) =>
            <li key={index}>
              <h3>{article.title}</h3>
              <p>{article.abstract}</p>
            </li>
          )}
        </ul>
      </React.Fragment>
    );
  }
}

export default TopStories;

Let's go over the changes we've made to TopStories.js. Most of this should be familiar from what we've learned about the useReducer() hook in the Counter example.

• First, we need to import useReducer from React. We'll also need to remove the useState import since we're no longer using it.
• Next, we need to import the two action creators that we'll use to generate our actions: getTopStoriesFailure and getTopStoriesSuccess.
• Next, outside of the TopStories component, we create our initial state that will be added as an argument to the useReducer() hook. We could instead put the initial state in a separate file, or even in top-stories-reducer.js, and import it into TopStories.js. Whatever you do, you should be consistent across your entire application.
• We remove the three useState() statements and replace them with a useReducer() hook, passing in the initialState and topStoriesReducer. We save the state and dispatch function that's returned from the useReducer() hook in the variables state and dispatch; remember that we can call these variables anything so long as it is descriptive of what it represents.
• Later in the useEffect() hook and API call logic, when we receive a successful response or a failure response, we use either of our two action creator functions to generate an action, and then we dispatch that action using the dispatch() function.
• Finally, the last step in this refactor is to destructure the error, isLoaded, and topStories variables from the state variable.

Now we can run our application and everything will be working correctly. In other words, our API application is complete! We now have the tools to make API calls with fetch() in React applications with both the useState() and useReducer() hooks.

Next Steps

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As you build React apps, we encourage you to continue to use hooks to manage state and avoid class components. That includes whether you use hooks in conjunction with a state library like Redux, or standalone. If you would like to learn how to make an API call in a class component, visit the React docs.

Also, keep in mind that there are many, many custom React hooks out there. Check out this excellent list of resources on hooks, which includes tutorials and links to various custom hooks. Among other things, these custom hooks offer the following additional functionality to function components:

• Handling form state
• Using the Fetch API
• Drawing SVGs
• Handling media queries

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API Project with React and the useReducer() Hook