Remove Duplicates

Working With Arraysmedium

Course · Section 11: Working With Arrays · Lecture 149: Simple Array Methods

Implement `removeDuplicates(arr)` that returns a new array with duplicate values removed, preserving the original order.

Input: removeDuplicates([1,2,2,3,3,3])

Output: [1,2,3]

Input: removeDuplicates(["a","b","a"])

Output: ["a","b"]

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Common pitfalls

Objects are compared by reference, so a Set will not dedupe equal-looking objects.

Approach & explanation (try first)

new Set keeps first occurrences in order; spreading returns the deduplicated array.

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