Workers Types Generator should generate env vars type as string

[boxcolli]

Current situation

Currently wrangler types makes env vars type as concrete value. (using wrangler 3.62.0)

For example, this configuration

# wrangler.toml
[vars]
MY_VARIABLE = "production_value"

will be:

// worker-configuration.d.ts
interface Env {
  MY_VARIABLE: "production_value";
}

Problem

When I want to set different values to each environment like,

# wrangler.toml
[vars]
WHICH_ENV = "development"

[env.preview.vars]
WHICH_ENV = "preview"

[env.production.vars]
WHICH_ENV = "production"

it generates

// worker-configuration.d.ts
interface Env {
  WHICH_ENV: "development";
}

and I can't compare the value in typescript code.

// compile error
export function createSession(env: Env) {
    switch (env.WHICH_ENV) {
        case "development":
        case "preview":
            return createMemorySessionStorage({ cookie: sessionCookie })        

        case "production":
        default:
            return createKVSessionStorage(env.KV_SESSION)
    }
}

Suggestion

So wrangler types command should generate env vars type as string.

Importance of the problem?

It is not quite a problem, because I can still manually change the type in worker-configuration.d.ts.

But I think making env vars comparable is intuitive and just right.