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Deep Flatten

A Closer Look at Functionsmedium

Course · Section 10: A Closer Look at Functions · Lecture 137: First-Class and Higher-Order Functions

Implement `deepFlatten(arr)` fully flattening arbitrarily nested arrays of numbers using recursion.

Sample tests

Input: deepFlatten([1,[2,[3,[4]]]])
Output: [1,2,3,4]
Input: deepFlatten([])
Output: []

+ 1 hidden test run on Submit.

Hints

Common pitfalls
  • Only flattening one level instead of recursing fully.
  • Treating non-array values as iterable.

Learning resources

  • MDN: Recursion
Approach & explanation (try first)

Recursing into nested arrays and collecting scalars flattens arbitrarily deep structures.

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