JavaScript
/Intermediate
Implement: Flatten Array
Definition
A highly common interview coding question: Write a function that takes an arbitrarily deeply nested array and flattens it into a 1D array without using the native `Array.flat()` method.
Explain Like I'm New
The interviewer wants to see if you understand Recursion and type checking (`Array.isArray`).
Real World Example
Flattening `[1, [2, [3, 4], 5]]` into `[1, 2, 3, 4, 5]`.
Common Use Cases
- •Recursion mastery
- •Interview screening
Interactive Example
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Interview Questions
basic
- How do you check if a variable is an array in JS?
intermediate
- Write a recursive solution to flatten an array.
advanced
- How would you flatten an array iteratively (without recursion) using a Stack?