Spiral number output

spiral.js

buildSpiral(5);

buildSpiral(4);

function buildSpiral(n) {
  const arr = range(n).map(() => range(n));
  
  const result = addLine(arr, range(n), range(n), 0);
  
  result.forEach(r => {
    console.log(
      r
      .map(i => `  ${i}`.slice(-2))
      .join(' ')
    )
  });
  console.log('-----------------------');
}

function range(n) {
  return [...Array(n).keys()];
}

function addLine(arr, line, column, currentNumber) {
  column.forEach(i => {
    arr[line[0]][i] = ++currentNumber;
  });
  
  line.shift();

  if (column.length) {
    return addColumn(arr, line, column.reverse(), currentNumber);
  }
  
  return arr;
}

function addColumn(arr, line, column, currentNumber) {
  line.forEach(i => {
    arr[i][column[0]] = ++currentNumber;
  });

  column.shift();

  if (line.length) {
    return addLine(arr, line.reverse(), column, currentNumber);
  }
  
  return arr;
}