How to use node-config in typescript?

Question

After installing node-config and @types/config:

yarn add config yarn add --dev @types/config 

And adding config as described in lorenwest/node-config:

// default.ts export default {   server: {     port: 4000,   },   logLevel: 'error', }; 

When I am trying to use in my app:

import config from 'config';  console.log(config.server); 

I am getting the error:

src/app.ts(19,53): error TS2339: Property 'server' does not exist on type 'IConfig'. 

Answer 1

I'm taking a slightly different approach - defining the variables in JavaScript, and accessing them in TypeScript.

Using the following folder structure:

├── config │   ├── custom-environment-variables.js │   ├── default.js │   ├── development.js │   └── production.js └── server     ├── config.ts     └── main.ts 

I define the configuration in the root config/ folder. For example:

// config/default.js module.exports = {   cache: false,   port: undefined  // Setting to undefined ensures the environment config must define it };  // config/development.js module.exports = {   port: '3000' }  // config/production.js module.exports = {   cache: true }  // config/custom-environment-variables.js module.exports = {   port: 'PORT' } 

Now, in TypeScript land, I define an interface to provide nicer autocomplete & documentation, and write some bridging code to pull in the config from node-config into my config map:

// server/config.ts import nodeConfig from 'config';  interface Config {   /** Whether assets should be cached or not. */   cache: boolean;    /** The port that the express server should bind to. */   port: string; }  const config: Config = {   cache: nodeConfig.get<boolean>('cache'),   port: nodeConfig.get<string>('port') };  export default config; 

Finally, I can now import and use my config variables inside any TypeScript code.

// server/main.ts import express from 'express'; import config from './config';  const { port } = config;  const app = express();  app.listen(port); 

This approach has the following benefits:

• We can use the rich and battle-tested features available from node-config without needing to re-invent the wheel
• We have a strongly-typed, well documented config map which can be imported and used from anywhere inside our TS code

Answer 2

config.get utility can be used to get the config values like so:

import config from 'config';  const port: number = config.get('server.port');