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Group By Utility

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01

Understand the problem

Write a utility groupBy(array, criteria) that groups array items by keys returned by the criteria callback or property path, with guards against prototype pollution.

arrayobject
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

Study the solution

💡 How to Think About This Problem

When implementing Group By Utility in an interview, the interviewer evaluates your core JavaScript capabilities, syntax familiarity, and edge-case handling.

1. Deconstructing the Requirements

To construct a robust solution:

  • Pre-conditions: Handle empty collections

Solution ready — 2 min read

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04

Run the code

JSSecure groupBy implementation
05

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