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Build a Nested Comments widget

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01

Understand the problem

Build a threaded comments UI with reply, collapse and delete.

ReactRecursionTree
02

Attempt it yourself

Sketch your approach before reading the solution — that's what interviews test.

Nudge consolestandby

Stuck? Beam a request up — the console returns a conceptual nudge that guides your logic without spoiling the implementation.

03

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Building a Nested Comments Widget in React

Mental model: Comments are a tree: each node has id, text, and replies[]. Render it with a recursive component. Adding a reply means finding the target node by id and appending a child — return a new tree so React re-renders. Recursion handles arbitrary depth.

Solution ready — 2 min read

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04

React solution

Complete solutionRun Playground
import React from 'react';
import NestedComments from './src/NestedComments';

export default function App() {
  return (
    <div style={{ fontFamily: 'sans-serif', padding: 20 }}>
      <h1>Nested Comments Demo</h1>
      <NestedComments />
    </div>
  );
}
05

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Dossier 26 of 87 decoded in the Frontend Machine Coding track. One more won't hurt.

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