Print aligned tables

aligned-table.js

function alignedTable({
  alignments = [],
  separator = '  ',
  prefix = '',
  suffix = '',
  newLine = '\n',
  rows = [],
} = {}) {
  function toString() {
    const lengths = {};
    const onlyNumbers = {};
    let table = '';

    rows.forEach((row, rowIndex) => {
      row.forEach((cell, cellIndex) => {
        cell = String(cell);

        lengths[cellIndex] = Math.max(lengths[cellIndex] || 0, cell.length);
        onlyNumbers[cellIndex] =
          (onlyNumbers[cellIndex] === undefined || onlyNumbers[cellIndex]) &&
          /^[0-9., ]*(\s*\w+)?$/.test(cell);
      });
    });

    rows.forEach((row, rowIndex) => {
      let line = prefix;
      row.forEach((cell, cellIndex) => {
        cell = String(cell);

        if (cellIndex !== 0) {
          line += separator;
        }
        const alignment =
          alignments[cellIndex] || (onlyNumbers[cellIndex] ? 'r' : 'l');
        if (alignment === 'r') {
          line += cell.padStart(lengths[cellIndex]);
        } else if (alignment === 'c') {
          line += cell
            .padStart(lengths[cellIndex] / 2 - cell.length / 2)
            .padEnd(lengths[cellIndex]);
        } else {
          line += cell.padEnd(lengths[cellIndex]);
        }
        line += suffix;
      });

      table += line + newLine;
    });

    return table;
  }

  return {
    row(...row) {
      rows.push(row);
    },

    print() {
      console.log(toString());
    },

    toString,
  };
}