Add functionality for reading env

Author: georg-schwarz

basics/package-lock.json

@@ -32,5 +32,8 @@
   "bugs": {
     "url": "https://github.com/jvalue/node-dry/issues"
   },
-  "homepage": "https://github.com/jvalue/node-dry#readme"
+  "homepage": "https://github.com/jvalue/node-dry#readme",
+  "dependencies": {
+    "@types/node": "^14.14.7"
+  }
 }

basics/package.json

@@ -0,0 +1,13 @@
+import { isEmpty } from './validators'
+
+export function readEnvOrDie (envName: string): string {
+  const env = process.env[envName]
+  if (isEmpty(env)) {
+    console.error(`Required environment variable ${envName} is not defined or empty`)
+    console.error('Unable to proceed with service')
+    process.exit(-2)
+  }
+
+  console.info(`[Environment Variable] ${envName} = ${env}`)
+  return env
+}

basics/src/env.ts

@@ -1,9 +1,11 @@
 import { sleep } from './sleep'
 import * as validators from './validators'
 import * as stringifiers from './stringifiers'
+import { readEnvOrDie } from './env'
 
 export {
   sleep,
   validators,
+  readEnvOrDie,
   stringifiers
 }

basics/src/index.ts

@@ -6,6 +6,10 @@ export function isString (x: unknown): x is string {
   return typeof x === 'string'
 }
 
+export function isEmpty (value: string | undefined): value is undefined {
+  return value === undefined || value === ''
+}
+
 export function isObject (x: unknown): x is object {
   return typeof x === 'object'
 }