eslint-relative-formatter.js

// The default ESLint formatter with relative paths.
// Forked from https://github.com/eslint/eslint/blob/main/lib/cli-engine/formatters/stylish.js

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

function pluralize(word, count) {
  return count === 1 ? word : `${word}s`
}

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

  results.forEach(result => {
    const messages = result.messages

    if (messages.length === 0) {
      return
    }

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

    // This is the only line that is different from the original stylish formatter.
    output += `${chalk.underline(path.relative(process.cwd(), result.filePath))}\n`

    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(/([^ ])\.$/u, '$1'),
          chalk.dim(message.ruleId || ''),
        ]
      }),
      {
        align: ['', 'r', 'l'],
        stringLength(str) {
          return stripAnsi(str).length
        },
      }
    )
      .split('\n')
      .map(el => el.replace(/(\d+)\s+(\d+)/u, (m, p1, p2) => chalk.dim(`${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),
          ' and ',
          fixableWarningCount,
          pluralize(' warning', fixableWarningCount),
          ' potentially fixable with the `--fix` option.\n',
        ].join('')
      )
    }
  }

  // Resets output color, for prevent change on top level
  return total > 0 ? chalk.reset(output) : ''
}