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Software Engineering Fundamentals questions require understanding of core concepts and practice. PracHub provides solutions with explanations to help you master software engineering fundamentals interviews.

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This is a medium difficulty Software Engineering Fundamentals question, commonly asked during Technical Screen rounds at Coinbase.

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This question is commonly asked for Software Engineer candidates at Coinbase during technical interviews.

Implement a blog feed with fetching and state

Q: Implement a blog feed with fetching and state

This question evaluates client-side React skills including state management, asynchronous data fetching, optimistic UI updates, and deterministic sorting and deletion behavior for a blog feed.

You are building a simple Blog Posts page (React). Implement the UI and client-side logic in incremental steps.

Data model

Assume each post has at least:

id: string
authorId: string
content: string
createdAt: ISO string
likeCount: number
lastLikedAt: ISO string | null (timestamp when this post most recently received a like; null if never)

Assume each user has:

id: string
name: string

Step 1 — Render local posts

Posts are initially available from a local JSON file (or in-memory constant).
Render a list of posts.

Step 2 — Add “create post”

Add a textarea and a submit button.
On submit, create a new post and update local React state so the UI updates immediately.
The newly created post must appear in the feed as if it was posted “now”.

Step 3 — Fetch posts + users; show “you”

Replace the local JSON source with API calls:

Fetch posts from an API endpoint (e.g., GET /api/posts ).
Each post contains authorId (not the author name).
Fetch user info so you can display author names (e.g., GET /api/users/:id ), and fetch the current user (e.g., GET /api/me ).
When rendering posts authored by the current user, display the author label as "you" instead of their username.

Step 4 — Sort by likes; allow delete for own posts

Sort posts by:
1. likeCount descending.
2. If likeCount is tied, the post that was most recently liked ( lastLikedAt descending) comes first.
For posts authored by the current user:
- show a Delete button.
- clicking Delete removes the post by updating local state (no server required for this step).
The ordering must remain correct after:
- creating a new post,
- deleting a post,
- likes changing (if the UI updates likeCount / lastLikedAt ).

Notes

You may assume reasonable API responses and can define any missing minor fields needed to meet the requirements (e.g., generating id /timestamps for new local posts).
Focus on correctness, resilience to async fetch timing, and clean state management.

You are building a simple Blog Posts page (React). Implement the UI and client-side logic in incremental steps.

Data model

Assume each post has at least:

id: string
authorId: string
content: string
createdAt: ISO string
likeCount: number
lastLikedAt: ISO string | null (timestamp when this post most recently received a like; null if never)

Assume each user has:

id: string
name: string

Step 1 — Render local posts

Posts are initially available from a local JSON file (or in-memory constant).
Render a list of posts.

Step 2 — Add “create post”

Add a textarea and a submit button.
On submit, create a new post and update local React state so the UI updates immediately.
The newly created post must appear in the feed as if it was posted “now”.

Step 3 — Fetch posts + users; show “you”

Replace the local JSON source with API calls:

Fetch posts from an API endpoint (e.g., GET /api/posts ).
Each post contains authorId (not the author name).
Fetch user info so you can display author names (e.g., GET /api/users/:id ), and fetch the current user (e.g., GET /api/me ).
When rendering posts authored by the current user, display the author label as "you" instead of their username.

Step 4 — Sort by likes; allow delete for own posts

Sort posts by:
1. likeCount descending.
2. If likeCount is tied, the post that was most recently liked ( lastLikedAt descending) comes first.
For posts authored by the current user:
- show a Delete button.
- clicking Delete removes the post by updating local state (no server required for this step).
The ordering must remain correct after:
- creating a new post,
- deleting a post,
- likes changing (if the UI updates likeCount / lastLikedAt ).

Notes

You may assume reasonable API responses and can define any missing minor fields needed to meet the requirements (e.g., generating id /timestamps for new local posts).
Focus on correctness, resilience to async fetch timing, and clean state management.

Implement a blog feed with fetching and state

Quick Overview

Implement a blog feed with fetching and state

Data model

Step 1 — Render local posts

Step 2 — Add “create post”

Step 3 — Fetch posts + users; show “you”

Step 4 — Sort by likes; allow delete for own posts

Notes

Write your answer

Implement a blog feed with fetching and state

Quick Overview

Implement a blog feed with fetching and state

Data model

Step 1 — Render local posts

Step 2 — Add “create post”

Step 3 — Fetch posts + users; show “you”

Step 4 — Sort by likes; allow delete for own posts

Notes

Write your answer