Question 1

What are the basics of regular expressions in JavaScript?

Accepted Answer

**Target Audience:** Engineers preparing for JavaScript fundamentals interviews. **Difficulty:** Medium > **How to read this doc:** Concepts are explained in plain language first, then tagged with 📌 Interview term:. Every match, capture-group, and statefulness claim below was actually run in Node. ## 1. Why This Even Matters — A Story First A regex with the global flag is like a bookmark left in a long document rather than a search that always starts from page one — each new sea

Question 2

What does the RegExp `v` flag (Unicode Sets) add over the `u` flag?

Accepted Answer

**Target Audience:** Engineers preparing for JavaScript fundamentals/regex interviews. **Difficulty:** Medium > **How to read this doc:** Concepts are explained in plain language first, then tagged with 📌 Interview term:. Every match/exclusion result below was actually run in Node (ES2024, Chrome 117+/Firefox 119+/Safari 17.4+/Node 20.12+). ## 1. Why This Even Matters — A Story First Describing "any fruit except citrus" using only a plain list-based menu (the `u` flag's characte

Question 3

How would you write a deep-clone function that correctly handles a self-referencing (circular) object without infinite recursion?

Accepted Answer

**Target Audience:** Engineers preparing for JavaScript object-manipulation interview questions. **Difficulty:** Medium > **How to read this doc:** Concepts are explained in plain language first, then tagged with 📌 Interview term:. Every result shown below is **real, captured output** from actually running the code in this doc on Node.js v24.19.0 — not illustrative sample output. ## 1. Why This Even Matters — A Story First Imagine photocopying a family tree poster where, somewhe

JAVASCRIPTDECODED.

Medium

What are the basics of regular expressions in JavaScript?

Hard

What does the RegExp `v` flag (Unicode Sets) add over the `u` flag?

How would you write a deep-clone function that correctly handles a self-referencing (circular) object without infinite recursion?