JS Built-ins
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ArrayArray.fromintermediate

Array.from() — generate even numbers with a map function

📖 Usage Example
Array.from([1, 2, 3], n => n * n)
// → [1, 4, 9]

Pass a mapping function as the second argument to Array.from() to transform each element.

Array.from() — with a mapping function

The second argument to Array.from() is a mapping function applied to each element as the array is built. This lets you combine creation and transformation in a single step.

Challenge: Implement createEvenNumbers that returns the first count positive even numbers: [2, 4, 6, …, count*2].

createEvenNumbers(5) // → [2, 4, 6, 8, 10]
createEvenNumbers(1) // → [2]
💡 Hints (2)
  • • Use index `i` inside the map function: `(i + 1) * 2` gives 2, 4, 6…
  • • The first argument `{ length: count }` controls how many elements are generated.