lambda-service/src/routes/getPageCountFromRoutes.js

let targetLevel = null
let level = 0

export default function(routes) {
  if (process.env.CODE_SPLITTING_LEVEL) {
    targetLevel = process.env.CODE_SPLITTING_LEVEL
  } else {
    targetLevel = 1
    const rootRoute = routes.filter(route => route.path === '/')[0]
    if (rootRoute && rootRoute.routes) {
      targetLevel = 2
    }
  }

  return countRoutes(routes)
}

function countRoutes(routes) {
  level += 1
  const ret = routes.reduce((memo, route) => {
    if (level <= targetLevel) {
      if (route.routes) {
        memo += countRoutes(route.routes) + 1
      } else {
        memo += 1
      }
    }
    return memo
  }, 0)
  level -= 1
  return ret
}