config without higher order function

config.js

const common = {}
let config = {}

export function setup = url => {
    van: {
    ...common,
    remoteDbUrl: process.env.REACT_APP_VAN_COUCHDB_URL || 'http://localhost:5984/',
    dateFormats: {
      long: 'D MMM, YYYY',
      week: 'YYYY-[W]WW'
    },
    appName: 'VAN',
    logoUrl: '',
    theme: '',
    hosts: [
      'dev.van.field.partners',
      'dev.van.field.local:3000',
      'staging.van.field.partners',
      'training.van.field.partners',
      'van.field.partners'
    ]
  },
  psm: {
    ...common,
    remoteDbUrl: process.env.REACT_APP_VAN_COUCHDB_URL || 'http://localhost:5984/',
    dateFormats: {
      long: 'D MMM, YYYY',
      week: 'YYYY-[W]WW'
    },
    appName: 'National Stock System',
    logoUrl: 'https://s3-eu-west-1.amazonaws.com/field-psm/assets/coat-of-arms-nigeria.svg',
    theme: 'psm',
    hosts: [
      'dev.nscip.field.supply',
      'dev.nscip.field.local:3000',
      'staging.nscip.field.supply',
      'nscip.field.supply'
    ]
  }  
  
  // somehow generate the config based on the passed in url
  // replace the config variable on module level
  config = generateFromUrl(url)
}

// this is used to access the config object
export const getConfig () => {
  return config 
}

index.js

// For using in one of the sub-apps

import { setConfig } from '@fielded/van-shared/build-lib/providers/config'

import Root from './root/Root'

setConfig(window.location)
render(<Root />, rootElement)

mycomponent.js

import { getConfig } from '@fielded/van-shared/build-lib/providers/config'

const MyComponent = ({ config }) => {
 const config = getConfig()
 return (<div>
    <pre>{JSON.stringify(config, false, 2)}</pre> 
  </div>)
}

export default MyComponentWithConfig

/*
testing
*/
         
it('choses van style sheet', t => {
  setConfig(vanurl)
  // render and make assertions
})         


it('choses psm style sheet', t => {
  setConfig(psmurl)
  // render and make assertions
})         

root.js

import React, { Component } from 'react'

import { setConfig } from '@fielded/van-shared/build-lib/providers/config'

import Loading from '../common/Loading'
import PreloadedStateProvider from './PreloadedStateProvider'
import { setConfig } from './common/config'

import { getPreloadedState } from './reducer'

class Root extends Component {
  state = {}
  constructor () {
    super()
    setConfig(window.location)
  }

  componentDidMount () {

    
    if (!this.state.preloadedState) {
      return getPreloadedState()
        .then(preloadedState => this.setState({preloadedState}))
    }
  }

  render () {
    if (!this.state.preloadedState) {
      return <Loading />
    }

    // ConfigProvider calls `resolveConfigFromLocation` passing the location object
    // and config options and populates the context.config with the correct values
    return (
        <PreloadedStateProvider
          preloadedState={this.state.preloadedState}
        />
    )
  }
}

export default Root