index.js

const getFeed = require('./lib/getFeed')
const formatter = require('./lib/formatter')
const minutesToMs = require('./lib/minutesToMs')
const send = require('./lib/send')
const template = require('./lib/template')
const includes = require('./lib/includes')

const [ABORT, SUCCESS] = ['abort', 'success']

/**
 * @param {string} webhook
 * @param {string} channel
 * @param {string} feed
 * @param {number} [interval=900] In minutes. Default: minutes
 * @param {object} [logger=console]
 * @returns {Promise<string>}
 */
module.exports = async function check ({
  webhook,
  channel,
  feed,
  interval = 15,
  logger = console,
  logFormat,
  emoji = ':rolled_up_newspaper:',
  dryRun
} = {}) {
  logger = formatter(logger, logFormat)

  try {
    if (!webhook || !feed) {
      logger.error(`Missing webhook or feed ${{ webhook, feed }}`)
      return ABORT
    }

    const lastCheck = new Date(Date.now() - minutesToMs(interval))
    const now = new Date()
    const { feedURL, include, exclude } = (
      (feed) => {
        if (typeof feed === 'object') {
          const [feedURL, { include, exclude }] = Object.entries(feed).pop()

          const [includeList, excludeList] = [include, exclude].map(
            list => list && Array.isArray(list)
              ? list
              : [list]
          )

          return { feedURL, include: includeList.filter(Boolean), exclude: excludeList.filter(Boolean) }
        }

        return { feedURL: feed, include: [], exclude: [] }
      }
    )(feed)

    const { title, lastBuildDate, pubDate, items } = await getFeed(feedURL)
    const lastUpdate = new Date(lastBuildDate || pubDate)

    if (lastUpdate < lastCheck) {
      logger.verbose(`Feed did not update since ${new Date(lastCheck)} in ${feedURL}`)
      return ABORT
    }

    const entries = items.filter(({ isoDate, pubDate }) => {
      const date = new Date(isoDate || pubDate)
      if (date < lastCheck) {
        // Too old
        return false
      }
      if (date > now) {
        // Future event
        return false
      }
      return true
    }
    ).filter(({ title = '', contentSnippet = '' }) => {
      const conditions = []

      if (include.length && !include.some(i => includes(title, i) || includes(contentSnippet, i))) {
        conditions.push(false)
      }

      if (exclude.length && exclude.some(i => includes(title, i) || includes(contentSnippet, i))) {
        conditions.push(false)
      }

      return !conditions.includes(false)
    })

    if (!entries.length) {
      logger.verbose(`There are no new entries since ${new Date(lastCheck)} in ${feedURL}`)
      return ABORT
    }

    logger.verbose(`Found an update in ${feedURL} since ${new Date(lastCheck)}`)

    const output = template({
      channel,
      username: title,
      entries,
      emoji
    })

    if (dryRun) {
      return Promise.resolve(JSON.stringify(output, null, 1))
    }

    return send(webhook, output).then(
      () => SUCCESS
    ).catch(
      logger.error
    )
  } catch (error) {
    logger.error(
      error instanceof Error
        ? [error.message, `Feed: ${feed}`, error.stack].join('\n')
        : `${error} feed: ${feed}`
    )
  }
}