Script to pad CSV columns (for readability)

pad_csv.js

const fs = require('fs');

const filterMap = (list, map) => {
  const mapped = [];

  for (let i = 0; i < list.length; i++) {
    const transformed = map(list[i]);
    if (transformed) {
      mapped.push(transformed);
    }
  }

  return mapped;
};

const readCSV = file => {
  const csv = fs.readFileSync(require.resolve(file), 'utf8');

  return csv.split('\n');
};

const transformByLine = (file, format) => {
  const csvSplit = readCSV(file);

  return filterMap(csvSplit, line => line && format(line));
};

const parsedCSV = transformByLine(
  './my.csv',
  line => line.split(',')
);

const padList = parsedCSV
  .reduce((acc, line) => {
    line.forEach((content, index) => {
      if (!acc[index] || content.length > acc[index]) {
        acc[index] = content.length;
      }
    });

    return acc;
  }, [])
  .map(pad => pad + 2);

const padByIndex = padList => line => {
  return line
    .map((item, index) => {
      if (padList[index]) {
        return item.padStart(padList[index], ' ');
      }

      throw new Error(`No padding specified at index ${index}`);
    })
    .join(',');
};

fs.writeFileSync('./padded.csv', parsedCSV.map(padByIndex(padList)).join('\n'));