MergeSort

const mergeSort = (arr1, arr2) => {
    if (arr1.length === 0) {
       return arr2;
    }
    
     if (arr2.length === 0) {
       return arr1;
    }
    
    const mergedArry = [];
    let i = 0;
    let j = 0;

    
   while (i < arr1.length && j < arr2.length) {
    if (arr1[i] < arr2[j]) {
      mergedArry.push(arr1[i]);
      i++;
    } else {
      mergedArry.push(arr2[j]);
      j++;
    }
  }
    
    return [...mergedArry, ...arr1.slice(i), ...arr2.slice(j)];
    
    
};

console.log(mergeSort([0,3,4], [5, 6, 35]));