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Francis Adediran
Francis Adediran

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How to add .env and use process.env to your typescript project

I recently came across this problem in my project and the usual google search/Stackoverflow readings lead to partial and confusing solutions.
So i’m going to document my solution, hopefully someone finds it useful.

First install dotenv package

npm install dotenv;
yarn add dotenv;

Import to the entry point of your code. This is usually your index.ts, main.ts or app.ts

import * as dotenv from 'dotenv';

//inside your starter code, do this

Now you are ready to use, process.env.ENVIRONMENT_VARIABLE with your project.

However, i will recommend creating a config module to put all your environment variables access. This approach has a lot of benefits such as:

  • ease of code refactoring: a single place to update, change any environment variable key or default value. This is better than doing All-files-search of a variable name.
  • ease of testing: you can mock or intercept this.
  • Clean code: this approach is modular and less typing.

Your config module could look like this. endpoints.config.ts

export default {
 UserBaseUrl: process.env.USER_SERVICE_URL ?? '',
 EtlUrl: process.env.ETL_SERVICE_URL ?? ''

Now in your code, you can do something like this

import endpoint from '../endpoints.config';
const user = await axios.get(endpoint.UserBaseUrl, { params})

That’s it!. Feel free to leave a comment if i missed anything or you are having issues with this.

Discussion (9)

mick62 profile image

When the app starts up it's crucial to first check whether all config parameters got a value (explicitly from an environment variables or via a default value).
This "fail early" behavior is important e.g. for apps deployed via kubernetes. If there is a problem the app (container/pod) should signal en error to kubernetes on start-up. So the attempt to deploy a new version fails and will be rolled back to the previous version.
Your example code would try to send a request to an empty url getting an inherited error w/o the chance to handle the root cause automatically.

allindeveloper profile image
Uchendu Precious

Please can you throw more light on this.. i am experiencing a similar issue. i have a react app deployed to kubernetes that's not reading the env variable

mick62 profile image
mick62 • Edited on

Our app reads environment variables at start-up like this:

const envVarReader = new EnvVarReader();
export const envVar = {
UserBaseUrl: envVarReader.getURL('USER_SERVICE_URL'),
EtlUrl: envVarReader.getURL('ETL_SERVICE_URL')
envVarReader.checkVariables() // will throw an exception in case of errors
// with a message containing descriptions for all found problems

I wrote a small class 'EnvVarReader' which reads from 'process.env', checks and transforms the string values to the expected type. A missing or malformed URL will e.g. result in an exception thrown by 'checkVariables' at start-up.

Project time pressure kept me from making class 'EnvVarReader' available on github until now. But it seems I should take my time to just do that now.

Thread Thread
allindeveloper profile image
Uchendu Precious

Thanks for the clarity

frankfont profile image
Frank Font

Thanks for sharing! Last year I was looking for something like this and it would have helped!

rongem profile image

Good idea, but doesn't work for me. Fields always stay empty. Making fields to functions workd though.

ruberoni profile image
Ruben Paredes

For the people still with problems configuring dotenv, in its official repository is a guide just for typescript:

mehtabahmed176 profile image
Mehtab Ahmed

Thank you so so much, "google search/Stackoverflow readings lead to partial and confusing solutions" the same happened to me.

codenamecookie profile image

Im getting: npm ERR! code EINVALIDTAGNAME