extend type define of NodeJS.Process.env

[GongT]

installed: registry:dt/node#6.0.0+20160907103612

current content:

 export interface Process extends EventEmitter {
/// ....
    env: any;
/// ....
}

may change to:

export interface EnvironmentVariables {
    [key: string]: string;
}
export interface Process extends EventEmitter {
/// ....
    env: NodeJS.EnvironmentVariables;
/// ....
}

then users can extend env in their own .d.ts:

declare namespace NodeJS {
    export interface EnvironmentVariables {
        SOME_THING: string;
        SOME_OTHER_THING: string;
    }
}

currently this will cause error TS2403: Subsequent variable declarations must have the same type. Variable 'env' must be of type 'any', but here has type 'IProcessEnv':

interface IProcessEnv {
    SOME_THING: string;
    SOME_OTHER_THING: string;
}
declare namespace NodeJS {
    export interface Process {
        env: IProcessEnv;
    }
}

[blakeembrey]

The dt definition comes from https://github.com/DefinitelyTyped/DefinitelyTyped. This should be possible if you install this definition (which is env~node).

[blakeembrey]

Even then, I never got the code you posted to work. I tried different approaches, but nothing worked on the current TypeScript release unless you're using 2.0 or something.

Edit: Someone let me know if they have better luck and then we can change it from an inline type to an interface called Env.

[GongT]

I'm using typescript>2.0 ... LOL

tsc --version
Version 2.1.0-dev.20160905

[voxlet]

@blakeembrey

Edit: Someone let me know if they have better luck and then we can change it from an inline type to an interface called Env.

Confirmed this approach works with the current 2.0.6 TypeScript release.
This would be especially useful when using the TSLint no-string-literal rule, which currently needs liberal sprinkling of tslint:disable comment flags when accessing anything other than PATH.

[blakeembrey]

I always disable that rule unfortunately, TypeScript development just kind of requires it because you can't access index signatures without it. It'd be nice if TypeScript allowed process.env.hello with an index signature, but it doesn't.

[voxlet]

Yes, I guess that's true if you need to interface with a lot of external libraries. For my own code, though, I always define separate properties and use index signatures only for dynamic access.

Anyways, I went ahead and made a PR with the changes, if this is still up for consideration!

[xeoneux]

@blakeembrey why do I not see these changes when I install @types/node? Are they not published yet?

[blakeembrey]

This repo has nothing to do with NPM. Those come from DefinitelyTyped.

[xeoneux]

@blakeembrey how do I install these types then?

[blakeembrey]

This whole organisation is used for Typings, if you aren't using Typings, you can't. We've been waiting a year for microsoft/types-publisher#4 to make it possible.

[xeoneux]

@blakeembrey is typings still in development or @types is the official solution?

[blakeembrey]

Typings is stable and any issues will continue to be fixed, but it's in a deprecated state and I'd recommend using @types.