special-dispatch-app/app/services/api.js

const app = require('../app')
const _ = require('lodash')

app.run(function(api) {
  api.statistics = () => api.get('/api/statistics')

  let locations = null
  api.locations = () => locations || (locations = api.get('/api/locations'))

  let locationsDictionary = null
  api.locationsDictionary = () => locationsDictionary || (locationsDictionary = api.locations().then(locations => 
    _.fromPairs(locations.map(loc => [loc.key, loc]))
  ))
  api.location = (key) => api.locations().then(async locations =>
    (await api.locationsDictionary())[key]
  )
  let staffMembers = null
  api.staffMembers = () => staffMembers || (staffMembers = api.get('/api/staff-members'))

  let staffMemberDictionary = null
  api.staffMemberDictionary = () => staffMemberDictionary || (staffMemberDictionary = api.staffMembers().then(staffMembers =>
    _.fromPairs(staffMembers.map(sm => [sm.id, sm]))
  ))
})