Question 1

Describe the React component lifecycle.

Accepted Answer

**Target Audience:** Engineers preparing for React interviews — assumes hooks basics. **Difficulty:** Medium > **How to read this doc:** Concepts are explained in plain language first, then tagged with 📌 Interview term:. Every ordering below is **executed output from React 19.2.8**, not a description — the raw sequences are in sections 3 and 5. ## 1. Why This Even Matters — A Story First A market stall has three moments: setting up before opening, adjusting through the day as st

Question 2

Server Actions — how do mutations work without API routes in Next.js 15?

Accepted Answer

**Target Audience:** Engineers preparing for Next.js interviews — assumes what the directive does. **Difficulty:** Medium > **How to read this doc:** Concepts are explained in plain language first, then tagged with 📌 Interview term:. **A note on verification:** this needs a running Next.js server and there is none here, so the workflow was **not executed**. The React-level pieces it builds

Question 3

Explain React Suspense and its use cases.

Accepted Answer

**Target Audience:** Engineers preparing for React interviews — assumes components and promises. **Difficulty:** Medium > **How to read this doc:** Concepts are explained in plain language first, then tagged with 📌 Interview term:. The suspension behaviour in section 3 was produced by rendering a pending promise through use() on React 19.2.8 and reading the DOM before and after it resolved. ## 1. Why This Even Matters — A Story First In a restaurant, individual dish

Question 4

Why does updating Context re-render all its consumers, and how do you fix it?

Accepted Answer

**Target Audience:** Engineers preparing for senior React interviews — assumes Context and memo. **Difficulty:** Hard > **How to read this doc:** Concepts are explained in plain language first, then tagged with 📌 Interview term:. Every render count below was measured on React 19.2.8 with memo-wrapped consumers, so an ordinary parent re-render was already blocked — anything that still rendered got through via context. ## 1. Why This Even Matters — A Story First A mai

REACT.JSDECODED.

Medium

Describe the React component lifecycle.

Server Actions — how do mutations work without API routes in Next.js 15?

Explain React Suspense and its use cases.

Hard

Why does updating Context re-render all its consumers, and how do you fix it?