Arrays & Array Methods (map, filter, reduce)

What array transformation is being performed?

const data = [1, 2, 3, 4, 5];
const chunks = data.reduce((acc, item, index) => {
  const chunkIndex = Math.floor(index / 2);
  if (!acc[chunkIndex]) acc[chunkIndex] = [];
  acc[chunkIndex].push(item);
  return acc;
}, []);

Sorting into groups
Splitting into pairs
This reduces array into chunks of size 2: 1) Uses index to determine chunk position, 2) Creates new chunk array when needed, 3) Pushes items into appropriate chunks, 4) Results in [[1,2], [3,4], [5]], 5) Handles incomplete final chunk gracefully, 6) More flexible than slice-based chunking, 7) Common pattern for batch processing, 8) Useful for pagination or data grouping.
Creating subarrays
Reversing elements

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