diff --git a/4-binary/01-arraybuffer-binary-arrays/01-concat/_js.view/solution.js b/4-binary/01-arraybuffer-binary-arrays/01-concat/_js.view/solution.js
@@ -1,13 +1,13 @@
function concat(arrays) {
-  // sum of individual array lengths
  let totalLength = arrays.reduce((acc, value) => acc + value.length, 0);

  if (!arrays.length) return null;

  let result = new Uint8Array(totalLength);

-  // for each array - copy it over result
-  // next array is copied right after the previous one
  let length = 0;
  for(let array of arrays) {
    result.set(array, length);