Premium

Median of Array

By FrontendAtlas Team · Updated Jan 31, 2026

Return the median of a list of numbers. For even length, return the average of the two middle values. Do not mutate the input.

What you’ll build / What this tests

This premium javascript coding focuses on Median of Array. You’ll apply arrays and numbers thinking with easy level constraints. The prompt emphasizes Return the median of a list of numbers. For even length, return the average of the….

Learning goals

Translate the prompt into a clear javascript API signature and return shape.
Apply arrays, numbers, math techniques to implement median of array.
Handle easy edge cases without sacrificing readability.
Reason about time/space complexity and trade-offs in javascript.

Key decisions to discuss

Define the exact input/output contract before coding.
Choose iteration vs higher-order methods for readability.
Prioritize predictable edge-case handling over micro-optimizations.

Evaluation rubric

Correctness: covers required behaviors and edge cases.
Clarity: readable structure and predictable control flow.
Complexity: avoids unnecessary work for large inputs.
API discipline: no mutation of inputs; returns expected shape.
Testability: solution is easy to unit test.

Constraints / Requirements

Preserve input order and handle empty arrays safely.
Do not mutate inputs; return a new sorted output.
Do not mutate input arrays; preserve item order.
Handle empty or missing inputs without throwing errors.
Keep runtime close to linear time where possible.
Prefer a pure function: no side effects beyond the return value.

Mini snippet (usage only)

// Example usage
const nums = /* median of array input */;
const result = median(nums);
console.log(result);

// Edge case check
const empty = nums ?? null;
const fallback = median(nums);
console.log(fallback);

// Expected: describe output shape, not the implementation
// (no solution code in preview)

Common pitfalls

Mutating inputs instead of returning a new value.
Skipping edge cases like empty input, duplicates, or nulls.
Overlooking time complexity for large inputs.