React Javascript environment config for various URL rules. Used in my React Native project.

react_env_selector.js

/*
 * Configure various url rules per environment
 * Use `envSelector` and createSelector hooks to load env.json file
 * By Precious Akin
*/
import { createSelector } from 'reselect';

import ENV_FILE from '../../env.json';

const envSelector = () => ENV_FILE;

export const apiURL = createSelector(
  envSelector,
  ENV => {
      switch (ENV.network) {
          case 'dev':
              return `http://${ENV.offline_host || '0.0.0.0'}:9100`
          case 'staging':
              return ''
          case 'production':
              return 'https://prod-app.com'
          default:
              return 'https://staging-app.com'
      }
  }
);

Here is the json schema

{
"network": "production",
"offline_host": "127.0.0.1",
}

Call function in axios or fetch
let health_link = await axios.get(${apiURL}/health);