Allow a fallback value on get env var

Author: wildjames

packages/deploymentUtils/src/config/index.ts

@@ -1,20 +1,23 @@
 import {CloudFormationClient, ListExportsCommand} from "@aws-sdk/client-cloudformation"
 
-export function getConfigFromEnvVar(varName: string): string {
+export function getConfigFromEnvVar(varName: string, defaultValue: string | undefined = undefined): string {
   const value = process.env[varName]
   if (!value) {
+    if (defaultValue) {
+      return defaultValue
+    }
     throw new Error(`Environment variable ${varName} is not set`)
   }
   return value
 }
 
-export function getBooleanConfigFromEnvVar(varName: string): boolean {
-  const value = getConfigFromEnvVar(varName)
+export function getBooleanConfigFromEnvVar(varName: string, defaultValue: string | undefined = undefined): boolean {
+  const value = getConfigFromEnvVar(varName, defaultValue)
   return value.toLowerCase() === "true"
 }
 
-export function getNumberConfigFromEnvVar(varName: string): number {
-  const value = getConfigFromEnvVar(varName)
+export function getNumberConfigFromEnvVar(varName: string, defaultValue: string | undefined = undefined): number {
+  const value = getConfigFromEnvVar(varName, defaultValue)
   return Number(value)
 }
 

packages/deploymentUtils/tests/config/index.test.ts

@@ -102,6 +102,12 @@ describe("config helpers", () => {
       .toThrow("Environment variable MISSING is not set")
   })
 
+  test("getConfigFromEnvVar uses the default value when provided", () => {
+    delete process.env.OPTIONAL
+
+    expect(getConfigFromEnvVar("OPTIONAL", "defaultValue")).toBe("defaultValue")
+  })
+
   test("getBooleanConfigFromEnvVar maps string booleans", () => {
     process.env.FEATURE_FLAG = "true"
     process.env.OTHER_FLAG = "false"