Basic React exercise

App.jsx

import { useState, useEffect } from "react";
import blogs from "./blogs";
import "./App.css";

// Task:
//  - Update the `useBlogPosts` hook to "fetch" blog posts using the
//    `getBlogPosts` function. It should return blog posts (if we have them), an
//    error (if it exists) and the loading state.
//  - Update the `Blog` component to render each blog post once they have been
//    fetched. Make sure you handle error cases if the fetch fails or if we
//    don't have a blogId prop.
//  - When your app is working, consider how you have modeled it and how you
//    might improve it. Can some of the Blog be split into a separate component?
//    Could you reconsider how the state is managed? What would make this app
//    code maintainable and more resiliant to potential errors?

// Notes:
//  - Notice that `App` is what is exported and is responsible for setting the
//    blogId. You can set a different blogId here to be used by `Blog`.
//  - `getBlogPosts` is a function that accepts a blog ID. It will "fetch" posts
//    (this is fake for demo purposes but it works the same way as it would a
//    normal database request, so you will have a loading period and potential
//    for errors).
//  - When `getBlogPosts` resolves you will get an array of blog post objects.
//    Each object has an `id`, a `name`, and `content` properties.
//  - If you pass an invalid ID the request will result in an error.
//  - Valid blog IDs are 1, 2, or 3
//  - When thinking about how to render each blog post, consider that you are
//    working with a JavaScript array of objects. Remember that JSX is just an
//    abstraction of plain JavaScript that *looks* like HTML, but it's still
//    JavaScript! This means that you can work with JavaScript directly in your
//    component. You will need to use some sort of JS expression to render the
//    blog post data you're working with. Further reading:
//      - https://reactjs.org/docs/introducing-jsx.html#embedding-expressions-in-jsx
//      - https://reactjs.org/docs/lists-and-keys.html#embedding-map-in-jsx

function App() {
  return (
    <div className="App">
      <Blog blogId={2} />
    </div>
  );
}

function Blog(props) {
  let { blogId } = props;
  let { blogPosts, error, loading } = useBlogPosts(blogId);

  if (!props.blogId) {
    return <p>Error</p>;
  }

  if (loading) {
    return <p>Loading...</p>;
  }
  if (error) {
    return <p>{error}</p>;
  }
  if (blogPosts) {
    /* render each blog post's name and content */
    return (
      <ul>
        {blogPosts.map((post) => {
          return <li key={post.id}>{post.name}</li>;
        })}
      </ul>
    );
  }
}

/** @param {string|number} blogId */
function useBlogPosts(blogId) {
  let [loading, setLoading] = useState(true);
  let [blogPosts, setBlogPosts] = useState(null);
  let [error, setError] = useState(null);

  useEffect(() => {
    let isCurrentEffect = true;
    setLoading(true);
    setBlogPosts(null);
    setError(false);

    getBlogPosts(blogId)
      .then((posts) => {
        /* what now? */
      })
      .catch((error) => {
        /* handle errors! */
      });

    return () => {
      isCurrentEffect = false;
    };
  }, [blogId]);

  return {
    /** @type {typeof blogs['string']|null} */
    blogPosts,
    /** @type {string|null} */
    error,
    /** @type {boolean} */
    loading,
  };
}

export default App;

/** @param {string|number} blogId */
function getBlogPosts(blogId) {
  /** @type {Promise<typeof blogs['string']>} */
  let promise = new Promise((res, rej) => {
    blogId = String(blogId);
    if (!(blogId in blogs)) {
      return setTimeout(() => {
        return rej("Invalid blog ID");
      }, Math.round(Math.min(Math.random() * 1000, 500)));
    }
    let timeoutMs = Math.round(Math.min(Math.random() * 3000, 1500));
    setTimeout(() => {
      if (Math.random() > 0.25) {
        res(blogs[blogId]);
      } else {
        rej("Uh oh, something went wrong! Please try again.");
      }
    }, timeoutMs);
  });
  return promise;
}

blogs.js

/** @type {Record<string, Array<{ id: number; name: string; content: string; }>>} */
const BLOGS = {
  1: [
    {
      id: 0,
      name: "Lorem ipsum dolor",
      content:
        "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.",
    },
    {
      id: 1,
      name: "Sed ut perspiciatis",
      content:
        "Sed ut perspiciatis unde omnis iste natus error sit voluptatem accusantium doloremque laudantium, totam rem aperiam, eaque ipsa quae ab illo inventore veritatis et quasi architecto beatae vitae dicta sunt explicabo",
    },
    {
      id: 2,
      name: "Nemo enim ipsam voluptatem",
      content:
        "Nemo enim ipsam voluptatem quia voluptas sit aspernatur aut odit aut fugit, sed quia consequuntur magni dolores eos qui ratione voluptatem sequi nesciunt. Neque porro quisquam est, qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit, sed quia non numquam eius modi tempora incidunt ut labore et dolore magnam aliquam quaerat voluptatem. Ut enim ad minima veniam, quis nostrum exercitationem ullam corporis suscipit laboriosam, nisi ut aliquid ex ea commodi consequatur?",
    },
    {
      id: 3,
      name: "Quis autem vel eum iure reprehenderit",
      content:
        "Quis autem vel eum iure reprehenderit qui in ea voluptate velit esse quam nihil molestiae consequatur, vel illum qui dolorem eum fugiat quo voluptas nulla pariatur.",
    },
    {
      id: 4,
      name: "At vero eos et accusamus",
      content:
        "At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident.",
    },
  ],
  2: [
    {
      id: 5,
      name: "Similique sunt in culpa qui officia",
      content:
        "Similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga. Et harum quidem rerum facilis est et expedita distinctio.",
    },
    {
      id: 6,
      name: "Nam libero tempore",
      content:
        "Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus. Temporibus autem quibusdam et aut officiis debitis aut rerum necessitatibus saepe eveniet ut et voluptates repudiandae sint et molestiae non recusandae.",
    },
    {
      id: 7,
      name: "Itaque earum rerum hic tenetur",
      content:
        "Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.",
    },
  ],
  3: [
    {
      id: 8,
      name: "Nullam dictum felis",
      content:
        "Nullam dictum felis eu pede mollis pretium. Integer tincidunt. Cras dapibus. Vivamus elementum semper nisi. Aenean vulputate eleifend tellus. Aenean leo ligula, porttitor eu, consequat vitae, eleifend ac, enim. Aliquam lorem ante, dapibus in, viverra quis, feugiat a, tellus.",
    },
    {
      id: 9,
      name: "Phasellus viverra nulla",
      content:
        "Phasellus viverra nulla ut metus varius laoreet. Quisque rutrum. Aenean imperdiet. Etiam ultricies nisi vel augue. Curabitur ullamcorper ultricies nisi. Nam eget dui. Etiam rhoncus.",
    },
    {
      id: 10,
      name: "Maecenas tempus, tellus eget condimentum rhoncus",
      content:
        "Maecenas tempus, tellus eget condimentum rhoncus, sem quam semper libero, sit amet adipiscing sem neque sed ipsum. Nam quam nunc, blandit vel, luctus pulvinar, hendrerit id, lorem. Maecenas nec odio et ante tincidunt tempus.",
    },
    {
      id: 11,
      name: "Donec vitae sapien ut libero venenatis",
      content:
        "Donec vitae sapien ut libero venenatis faucibus. Nullam quis ante. Etiam sit amet orci eget eros faucibus tincidunt. Duis leo. Sed fringilla mauris sit amet nibh. Donec sodales sagittis magna. Sed consequat, leo eget bibendum sodales, augue velit cursus nunc.",
    },
  ],
};

export default BLOGS;