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Double Every Element

Working With Arrayseasy

Course · Section 11: Working With Arrays · Lecture 156: Data Transformations: map, filter, reduce

Implement `doubleAll(arr)` that returns a new array where every number has been multiplied by 2.

Sample tests

Input: doubleAll([1,2,3])
Output: [2,4,6]
Input: doubleAll([])
Output: []

+ 1 hidden test run on Submit.

Hints

Common pitfalls
  • Mutating the source array in a loop instead of mapping.

Learning resources

  • MDN: Array.prototype.map
Approach & explanation (try first)

map produces a new array with each value doubled.

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