Create dynamic type from environment variable in typescript

Question

There is a type that needs to be created in order to have custom strings inside. Something like:

type Names = { customName: "name1" | "name2" }

Since, what is planned is to have the "nameX" called from .env variables, I'd like to be able to do something like this:

type Names = {customName: process.env.name1 |  process.env.name2 }

Instead, as a result, the process. is not recognized Cannot find namespace 'process'.

Skyone · Accepted Answer · 2022-11-04 08:01:05Z

3

process.env is an Object, not a type!

I think what you're trying to say is

type Names = {
    customName: typeof process.env.name1 | typeof process.env.name2
}

However, the type definition of process.env is

interface ProcessEnv extends Dict<string> {
    TZ?: string;
}

So if you want to achieve your purpose, you need to redefine process.env like this

declare global {
    namespace NodeJS {
        interface ProcessEnv {
            name1?: string
            name2?: string
        }
    }
}

answered Nov 4, 2022 at 8:00

Skyone

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