Use DRY for React routes

routes.js

import { generatePath } from 'react-router'
/**
  Example:
    const RouteAdminPartners = makeRoute('/admin/partners/:partnerId?')

    console.log(RouteAdminPartners.pattern)
    > '/admin/partners/:partnerId?'

    console.log(RouteAdminPartners({ partnerId: 123 }))
    > '/admin/partners/123'

    console.log(RouteAdminPartners.toUrl({ partnerId: 123 }))
    > '/admin/partners/123'

    console.log(RouteAdminPartners.toUrl())
    > '/admin/partners'
 */
function makeRoute (pattern) {
  const routeHandler = {
    get: function(target, prop) {
      if (prop === 'pattern') {
        return target()
      } else if (prop === 'toUrl') {
        return function(paramsMap) {
          return generatePath(pattern, arguments[0])
        }
      }
    },

    apply: function(target, thisArg, argumentsList) {
      return generatePath(pattern, argumentsList[0])
    }
  }
  return new Proxy(() => pattern, routeHandler)
}