Get all number pairs which [[a, b], a + b = value], for a given value

allAddentPairsInArr.js

function findPairsInSorted(arr, value) {
  let results = [];
  let len = arr ? arr.length : 0;
  if (len < 2) {
    return results;
  }
  for (let i = 0, j = len - 1; i < j;) {
    let diff = value - arr[i];
    if (diff < arr[j]) {
      j--;
    }
    else if (diff > arr[j]) {
      i++;
    }
    else {
      results.push([arr[i++], arr[j--]]);
    }
  }
  return results;
}

function solve(arr, value) {
  let sortedArr = arr.sort((a, b) => a - b);
  return findPairsInSorted(sortedArr, value);
}

solve([ 3, 4, 5, -2, 10, 11, 12, -1, 0, 7, 8 ], 10);