Dotenv: introduce strict mode

[capaj]

would be cool if we could have a similar feature like https://github.com/jeffijoe/keyblade provides for https://github.com/jeffijoe/yenv- throwing when an undefined system variable is accessed.

[zenflow]

I don't think it's possible with dotenv. The env variables are accessed from the normal process.env object so we don't have the control to throw an error

[capaj]

you can use a proxy to trap any access to a property on that object.

I know it's not possible currently. This is a feature request.

[zenflow]

Ah! So it is possible. Cool idea and really cool approach!

But this behavior seems orthogonal to the purpose of dotenv (loading variables from a file), i.e. you could make a package that does this independent of dotenv and it could be used with or without dotenv.

For that reason, and since the maintainer likes to keep the core very lean, I think it might be better as a separate package.

[maxbeatty]

sorry, I don't 100% understand what you're asking for. can you provide an example?

[zenflow]

As I understand it:

.env

DB_HSOT=localhost

main.js

require('dotenv').config()
const host = process.env.DB_HOST 
// The proposal is that the above line throws an error since DB_HOST does not exist

[capaj]

@zenflow exactly right. It would mean that dotenv would require proxies to work so you'd have to bump required node version to 6 and newer.

[maxbeatty]

check out the bottom of the README. there are existing modules built on top of dotenv that provide this functionality

[capaj]

no there are not. Explicitly enumerating required variables is not the same as this. No worries, I'll just use yenv instead of dotenv 😎