pino-logfmt/src/levels.js

Logfmt transport for pino

/**
 * Serialize levels to labels mapping.
 *
 * @param {Record<number, string>} levelsToLabels
 * @returns {string}
 */
export function serialize (levelsToLabels) {
  return Object.entries(levelsToLabels)
    .map(([key, value]) => `${key}:${value}`)
    .join(',')
}

export class InvalidLevelLabelFormatError extends Error {
  name = InvalidLevelLabelFormatError.name

  constructor () {
    super('An invalid level to label mapping was passed, the correct format is "<level>:<label>". Such as "10:trace,20:debug,30:info"')
  }
}

/**
 * Parse serialized level to label.
 *
 * @param {string }serialized
 * @returns {Record<number, string>}
 */
export function parse (serialized) {
  if (!isFormatValid(serialized)) { throw new InvalidLevelLabelFormatError() }

  return Object.fromEntries(serialized.split(',')
    .map(levelAndLabel => levelAndLabel.split(':'))
    .map(([level, label]) => [parseInt(level), label]))
}

/**
 * Verify that the format is correct.
 *
 * @param {string} serialized
 * @returns {boolean}
 */
function isFormatValid (serialized) {
  const regex = /^((\d+):(\w+),?)+$/i
  return regex.test(serialized)
}