CrawlSELIC.js

import 'isomorphic-fetch'
import cheerio from 'cheerio'
import moment from 'moment-timezone'
import BigNumber from 'bignumber.js'

export const crawlSELIC = async () => {
  const page = await fetch(
    'http://idg.receita.fazenda.gov.br/orientacao/tributaria/pagamentos-e-parcelamentos/taxa-de-juros-selic',
  )

  const $ = cheerio.load(await page.text())

  return $('body table.listing:nth-of-type(5) tr')
    .toArray()
    .filter((_, i) => i !== 0)
    .map((item, month) => {
      return $(item)
        .children('td')
        .toArray()
        .filter((_, i) => i !== 0)
        .map((value, year) => ({
          date: moment
            .tz(`${2015 + year}-${String(1 + month).padStart(2, '0')}-01`, 'America/Sao_Paulo')
            .endOf('month')
            .startOf('day')
            .toDate(),
          selic: new BigNumber(
            $(value)
              .text()
              .replace(/[%,]/g, ''),
          )
            .dividedBy(100)
            .toNumber(),
        }))
    })
    .reduce((acc, item) => acc.concat(item), [])
    .sort((a, b) => a.date - b.date)
}