The Front-End JavaScript Round

This round belongs to front-end loops at HubSpot. Some intern candidates have reported it too, and back-end loops usually skip it. If yours includes it, know that it isn't about algorithms. You write small helpers in plain JavaScript with no framework, and two or three of them usually share one sitting. The same prompts keep turning up in reports going back to 2018, and they lean on prototypes, closures and this. Since the shapes repeat, a few evenings on them go a long way.

Each helper takes a few lines, and most of the hour goes to the questions that follow. What does this point to inside the helper? What does the closure keep alive after the outer function returns? Expect questions on bind and on rest parameters like ...args as well. Have your answers ready before the code is done.

Get the plain version working first, then talk through why it works. If you usually write front-end code inside a framework, practice these without one, since the round gives you none. The problems below run in six languages so you can test the logic, but the follow-ups assume JavaScript.

HubSpotPremium lesson · Coding round

The 3 HubSpot problems are below.

1. 1A Premium questionCoding · Medium · Frequently asked
2. 2A Premium questionCoding · Easy
3. 3A Premium questionCoding · Easy

Each with hints, the follow-up and a tested solution.

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