index.js

'use strict'
const fetch = require('isomorphic-fetch')
const hindex = require('h-index')
const escapeRegExp = require('lodash.escaperegexp')

function getRestLink (link) {
  const baseReg = new RegExp(
    escapeRegExp('https://api.github.com/user/') +
    '\\d+' +
    escapeRegExp('/repos?per_page=100&page='), 'g')
  const regex = new RegExp(
    escapeRegExp('https://api.github.com/user/') +
    '\\d+' +
    escapeRegExp('/repos?per_page=100&page=') + '(\\d+)', 'g')
  const next = +regex.exec(link)[1]
  const last = +regex.exec(link)[1]
  const base = baseReg.exec(link)[0]
  const res = []
  for (let i = next; i <= last; i++) res.push(base + i)
  return res
}

function getStats (user) {
  let initRateLimit
  let pageLen
  const rateLimit = 'https://api.github.com/rate_limit'
  const url = `https://api.github.com/users/${user}/repos?per_page=100`
  return fetch(rateLimit)
    .then(res => {
      // check if rate limit is exceeded
      if (res.statusText.toLowerCase() !== 'ok') {
        throw Error('connection error')
      }

      initRateLimit = +res.headers.get('X-RateLimit-Remaining')

      if (!initRateLimit) {
        throw Error('X-RateLimit-Remaining has reached 0!')
      }
      return fetch(url)
    })
    .then(res => {
      const link = res.headers.get('Link')
      initRateLimit = +res.headers.get('X-RateLimit-Remaining')
      const pages = [res.json()]

      if (link) {
        // get rest links of the user's repos
        const restLink = getRestLink(link)
        if (restLink.length > initRateLimit) {
          throw Error('The X-RateLimit-Remaining is not enough!')
        }
        initRateLimit = initRateLimit - restLink.length
        restLink.forEach(link => pages.push(
          fetch(link).then(res => res.json()))
        )
      }
      pageLen = pages.length
      return Promise.all(pages)
    })
    .then(pages => {
      let repos = []
      for (let page of pages) repos = repos.concat(page)

      return repos.map(repo => repo.stargazers_count)
    })
    .then(data => {
      console.log('User: ', user)
      console.log('The initial X-RateLimit-Remaining is: ', initRateLimit)
      console.log('The count of request is: ', pageLen)

      const res = hindex(data)
      res.repoCount = data.length
      return res
    })
    .catch(err => setTimeout(() => { throw err }, 0))
}

module.exports = getStats