index.js

const chalk = require('chalk');
const stripAnsi = require('strip-ansi');
const table = require('text-table');
const path = require('path');

/**
 * Given a word and a count, append an s if count is not one.
 * @param {string} word A word in its singular form.
 * @param {int} count A number controlling whether word should be pluralized.
 * @returns {string} The original word with an s on the end if count is not one.
 */
function pluralize(word, count) { return (count === 1 ? word : `${word}s`); }

module.exports = function(results) {
  let output = '\n';
  let errorCount = 0;
  let warningCount = 0;
  let fixableErrorCount = 0;
  let fixableWarningCount = 0;
  let summaryColor = 'yellow';

  results.forEach(result => {
    const messages = result.messages;
    const tableOpts = {
      align: ['', 'r', 'l'],
      stringLength(str) { return stripAnsi(str).length; },
    };

    output += `${chalk.underline(path.relative('.', result.filePath))}\n`;

    if (messages.length === 0) {
      output += `${table([
        ['', 0, 0, chalk.green('passing'), 'No linting issues', chalk.dim('success')],
      ], tableOpts).split('\n').map(el => el.replace(
        /(\d+)\s+(\d+)/,
        (m, p1, p2) => chalk.dim(`${p1}:${p2}`))
      ).join('\n')}\n\n`;
    }

    errorCount += result.errorCount;
    warningCount += result.warningCount;
    fixableErrorCount += result.fixableErrorCount;
    fixableWarningCount += result.fixableWarningCount;

    if (messages.length > 0) {
      output += `${table(
        messages.map(message => {
          let messageType;

          if (message.fatal || message.severity === 2) {
            messageType = chalk.red('error');
            summaryColor = 'red';
          } else {
            messageType = chalk.yellow('warning');
          }

          return [
            '',
            message.line || 0,
            message.column || 0,
            messageType,
            message.message.replace(/([^ ])\.$/, '$1'),
            chalk.dim(message.ruleId || ''),
          ];
        }),
        tableOpts
      ).split('\n').map(el => el.replace(
        /(\d+)\s+(\d+)/,
        (m, p1, p2) => chalk.dim(`${p1}:${p2}`))
      ).join('\n')}\n\n`;
    }
  });

  const total = errorCount + warningCount;

  if (total > 0) {
    output += chalk[summaryColor].bold([
      '\u2716 ', total, pluralize(' problem', total),
      ' (', errorCount, pluralize(' error', errorCount), ', ',
      warningCount, pluralize(' warning', warningCount), ')\n',
    ].join(''));

    if (fixableErrorCount > 0 || fixableWarningCount > 0) {
      output += chalk[summaryColor].bold([
        '  ', fixableErrorCount, pluralize(' error', fixableErrorCount), ', ',
        fixableWarningCount, pluralize(' warning', fixableWarningCount),
        ' potentially fixable with the `--fix` option.\n',
      ].join(''));
    }
  } else {
    summaryColor = 'green';
    output += chalk[summaryColor].bold(
      `\u2714 ${results.length} ${pluralize('file', results.length)} successfully linted.\n`);
  }
  return output;
  // return total > 0 ? output : '';
};