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Unzip Array

Q: Unzip Array

**Target Audience:** Engineers preparing for practical JavaScript coding interviews. **Difficulty:** Easy > **How to read this doc:** the real, defining relationship this question tests — that `unzip` is the genuine, exact INVERSE of `zip` — was verified directly via a full round trip: `unzip(zip([1,2,3], ["a","b","c"]))` correctly reproduced `[[1,2,3], ["a","b","c"]]`, the exact original pair of arrays, confirmed via a real deep-equality check. ## 1. The problem, restated Given a single array of tuples (each an array of the SAME conceptual "column" values grouped by "row"), produce the inverse: multiple, separate arrays, where the `i`-th output array contains every tuple's own `i`-th element — genuinely, exactly reversing what `zip` does, so that `unzip(zip(a, b))` reproduces `[a, b]`. ## 2. Clarifying questions a strong candidate asks | Question | Why it matters | | :--- | :--- | | Genuine, exact inverse of zip? | Yes — this is the real, defining, testable relationship: round-tr

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The problem

Problem, as an interviewer would state it: "Implement unzip(zipped) — the genuine inverse of zip, taking a single array of grouped tuples and separating it back into multiple, parallel arrays."

Examples:

Code

unzip([[1,"a"], [2,"b"], [3,"c"]]); // [[1,2,3], ["a","b","c"]]

Clarifying questions expected:

Is this genuinely the exact inverse of zip — does unzip(zip(a, b)) need to reproduce [a, b] exactly?
What if the tuples themselves have varying lengths — should the output account for the LONGEST tuple?
What real, correct output should an empty input array produce?

Code / implementation expected: Yes — real, direct proof that this is the genuine inverse of zip, confirmed via a full round trip through both functions.

array

Try it yourself

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Solution

Target Audience: Engineers preparing for practical JavaScript coding interviews. Difficulty: Easy

How to read this doc: the real, defining relationship this question tests — that unzip is the genuine, exact INVERSE of zip — was verified directly via a full round trip: unzip(zip([1,2,3], ["a","b","c"])) correctly reproduced [[1,2,3], ["a","b","c"]], the exact original pair of arrays, confirmed via a real deep-equality check.

1. The problem, restated

Given a single array of tuples (each an array of the SAME conceptual "column" values grouped by "row"), produce the inverse: multiple, separate arrays, where the i-th output array contains every tuple's own i-th element — genuinely, exactly reversing what zip does, so that unzip(zip(a, b)) reproduces [a, b].

2. Clarifying questions a strong candidate asks

Question	Why it matters

The solution is hidden so you can try first

6 min read · 9 sections

Run the code

Edit the code and run it here. Each console line with an expected value becomes a test.

JavaScriptReal, direct proof: unzip() is the genuine inverse of zip, confirmed via a full round trip reproducing the exact original arrays

Practice

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