function chunk(arr, size) {
  const out = [];
  for (let i = 0; i < arr.length; i += size) {
    out.push(arr.slice(i, i + size));
  }
  return out;
}
chunk([1, 2, 3, 4, 5], 2); // [[1, 2], [3, 4], [5]]

The last group may be shorter. A size larger than the array yields a single group; an empty array yields [].

sandbox.js

function chunk(arr, size) {
  // TODO
}

Output

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JavaScriptMedium9/15

Write chunk(arr, size) that splits an array into groups of size

By FrontendPro Editorial Team Updated 8/7/2026

Explore the JavaScript interview guide

Examples

Write chunk so that the following cases hold.

Inputchunk([1,2,3,4,5], 2)
Output[[1,2],[3,4],[5]]
Inputchunk([1,2,3], 3)
Output[[1,2,3]]
Inputchunk([1,2,3], 5)
Output[[1,2,3]]

1 more hidden test cases - 4 in total will be graded.

Answer

function chunk(arr, size) {
  const out = [];
  for (let i = 0; i < arr.length; i += size) {
    out.push(arr.slice(i, i + size));
  }
  return out;
}
chunk([1, 2, 3, 4, 5], 2); // [[1, 2], [3, 4], [5]]