date.js

const chrono = require('chrono-node')

const isoformat = '^\\d{4}-\\d{2}-\\d{2}' +       // Match YYYY-MM-DD
                  '((T\\d{2}:\\d{2}(:\\d{2})?)' + // Match THH:mm:ss
                  '(\\.\\d{1,6})?' +              // Match .sssss
                  '(Z|(\\+|-)\\d{2}:\\d{2})?)?$'  // Time zone (Z or +hh:mm)

function isIso (val) {
  const matcher = new RegExp(isoformat)
  return typeof val === 'string' && matcher.test(val) && !isNaN(Date.parse(val))
}

/**
 * Wrap a rule with validation and formatting logic.
 *
 * @param {Function} rule
 * @return {Function} wrapped
 */

function wrap (rule) {
  return function ($) {
    let value = rule($)
    if (!value) return

    // remove whitespace for easier parsing
    value = value.trim()

    // convert isodates to restringify, because sometimes they are truncated
    if (isIso(value)) return new Date(value).toISOString()

    // try to parse with the built-in date parser
    const native = new Date(value)
    if (!isNaN(native.getTime())) return native.toISOString()

    // try to parse a complex date string
    const parsed = chrono.parseDate(value)
    if (parsed) return parsed.toISOString()
  }
}

/**
 * Rules.
 */

module.exports = [
  wrap($ => $('meta[property="article:published_time"]').attr('content')),
  wrap($ => $('meta[name="dc.date"]').attr('content')),
  wrap($ => $('meta[name="dc.date.issued"]').attr('content')),
  wrap($ => $('meta[name="dc.date.created"]').attr('content')),
  wrap($ => $('meta[name="date"]').attr('content')),
  wrap($ => $('meta[name="dcterms.date"]').attr('content')),
  wrap($ => $('[itemprop="datePublished"]').attr('content')),
  wrap($ => $('time[itemprop*="pubdate"]').attr('datetime')),
  wrap($ => $('[property*="dc:date"]').attr('content')),
  wrap($ => $('[property*="dc:created"]').attr('content')),
  wrap($ => $('time[datetime][pubdate]').attr('datetime')),
  wrap($ => $('meta[name="sailthru.date"]').attr('content')),
  wrap($ => $('meta[property="book:release_date"]').attr('content')),
  wrap($ => $('time[datetime]').attr('datetime')),
  wrap($ => $('[class*="byline"]').text()),
  wrap($ => $('[class*="dateline"]').text()),
  wrap($ => $('[id*="date"]').text()),
  wrap($ => $('[class*="date"]').text()),
  wrap($ => $('[id*="publish"]').text()),
  wrap($ => $('[class*="publish"]').text()),
  wrap($ => $('[id*="post-timestamp"]').text()),
  wrap($ => $('[class*="post-timestamp"]').text()),
  wrap($ => $('[id*="post-meta"]').text()),
  wrap($ => $('[class*="post-meta"]').text()),
  wrap($ => $('[id*="metadata"]').text()),
  wrap($ => $('[class*="metadata"]').text()),
  wrap($ => $('[id*="time"]').text()),
  wrap($ => $('[class*="time"]').text())
]