Developer Guide April 11, 2026

3 JavaScript Questions Most Developers Get Wrong

A deep dive into the trickiest JavaScript interview questions from our archive, covering hoisting, closures, and type coercion.

JavaScript is notorious for its unexpected behaviors. Whether you are preparing for a frontend interview or just trying to sharpen your daily coding skills, you must master the fundamental quirks of the language.

In this guide, we break down some of the most highly-failed JavaScript questions from the CodeShot database. These questions specifically target unexpected outputs involving closures, hoisting, and object references.

1. The classic closure trap

Most junior developers expect this to behave symmetrically, but the event loop has other plans. Look closely at the execution context.

Senior
What gets logged to the console?

2. Type Coercion gone wrong

JavaScript's weakest link is often its loose typing. What exactly does the engine do when you try to manipulate undefined properties?

Mid
What does this output?

3. Floating Point Quirks

Simple math can sometimes break in JavaScript due to the IEEE 754 standard. This question catches almost everyone off guard.

Mid
What does this output?

How to improve your JavaScript confidence

The only way to build true confidence is repetition. Don't try to cram these concepts the night before an interview. By tackling one tricky JavaScript question every single day, your brain naturally rewires itself to spot these traps instantly.

Master concepts like this daily.

1 coding question a day. 60 seconds. Build real confidence.

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