Verify env vars with Node.js

.env

ARR1 = "value1 value2 value3"
ANOTHER = "test"
OPTIONAL_EXAMPLE = "optional test"

env.ts

export enum RequiredEnvVar {
  ARR1 = 'ARR1',
  ANOTHER = 'ANOTHER'
}

export enum OptionalEnvVar {
  OPTIONAL_EXAMPLE = 'OPTIONAL_EXAMPLE'
}

export type EnvVar = RequiredEnvVar | OptionalEnvVar

export const loadOptionalEnvVar = (key: EnvVar): string | undefined =>
  process.env[key]

export const loadEnvVar = (key: RequiredEnvVar): string =>
  loadOptionalEnvVar(key) as string

export const loadOptionalEnvVarArray = (
  key: EnvVar,
  separator = ' '
): string[] | undefined => {
  const env = process.env[key]
  return env?.split(separator)
}

export const loadEnvArray = (key: RequiredEnvVar, separator = ' '): string[] =>
  loadOptionalEnvVarArray(key, separator) as string[]

/** Verifies that all required environment variables exist.  */
export const envVarsAreCorrect = (): boolean => {
  return (
    Object.values(RequiredEnvVar).every(key => !!loadEnvVar(key)) &&
    Object.values(OptionalEnvVar).every(key => !!loadOptionalEnvVar(key))
  )
}