I have created a custom configuration file according to the docs - Custom Configuration Files Section. I can see that we can use this by injecting the ConfigService in the constructor() function of any other services and use it. However, my question about its usage in any random file that needs to access the process.env variables. For example, I have a util file that has a function (no classes with contructor) which just checks if process.env.NODE_ENV is in the given array of strings.

// nodeEnv.util.ts

export function isNodeEnvIn(envs: string[]): boolean {
    return envs.includes(process.env.NODE_ENV);
}

// config.ts

export default () => ({
    node: {
        env: process.env.NODE_ENV || 'local',
    },
})