@erwinv/envvar

$3

``shell
$ npm install @erwinv/envvar
`

$3

`TypeScript
import {
bool,
num,
str,
enu,
url,
EnvVars,
} from '@erwinv/envvar'

const envVars = new EnvVars({
NODE_ENV: enu(['development', 'staging', 'production']).default('development'),
HOST: str().default('localhost'),
PORT: num().required(),
DEBUG: bool().default(true),
JWT_SECRET: str().required(),
AUTH_API: url().default(new URL('http://gateway.localhost.localdomain/api/v1/auth')),
})

// fail fast but print all missing/incorrect-type ENV vars
// instead of bailing on the first error
const env = envVars.resolve()
`

#### Type Inference

TypeScript will correctly infer the resolved ENV vars types:

`TypeScript
// ...
const env = envVars.resolve()

export const config = {
env: env.NODE_ENV,
port: env.PORT,
debug: env.DEBUG,
jwt: {
privateKey: env.JWT_SECRET,
},
apiUrl: {
auth: env.AUTH_API,
},
}

/*
typeof config == {
env: "development" | "staging" | "production"
port: number
debug: boolean
jwt: {
privateKey: string
};
apiUrl: {
auth: URL
}
}
*/
`

This will enable autocompletion and real-time type-checking for supported IDE's (e.g., VSCode).

#### Generate dot env example file

Default values for optional ENV vars will be emitted on the output example file.

`TypeScript
const runningAsScript = require.main === module

if (runningAsScript) {
const [,, filepath] = process.argv

fs.promises.writeFile(filepath ?? './.env.example', envVars.example())
.then(() => process.exit(0))
.catch(e => {
console.error(e)
process.exit(1)
})
}
``