Handle undefined environment variables in resolveJoins

src/utils/resolveJoins.js

@@ -8,6 +8,10 @@ export default function resolveJoins(environment) {
 
   Object.keys(environment).forEach((key) => {
     const value = environment[key]
+    if (!value) {
+      return
+    }
+
     const joinArray = value['Fn::Join']
     const isJoin = Boolean(joinArray)
 

tests/endToEnd/environmentVariables/environmentVariables.test.js

@@ -0,0 +1,63 @@
+import { resolve } from 'path'
+import fetch from 'node-fetch'
+import {
+  joinUrl,
+  setup,
+  teardown,
+} from '../../integration/_testHelpers/index.js'
+
+jest.setTimeout(30000)
+
+describe('environment variables', () => {
+  const ENV_VAR_QUOTED = 'I am ENV_VAR_1'
+  const ENV_VAR_UNQUOTED = 'I am ENV_VAR_2'
+  const ENV_VAR_MAPPED = 'I am ENV_VAR_3'
+
+  // init
+  let json
+  beforeAll(async () => {
+    process.env.ENV_VAR_QUOTED = ENV_VAR_QUOTED
+    process.env.ENV_VAR_UNQUOTED = ENV_VAR_UNQUOTED
+    process.env.ENV_VAR_MAPPED_FROM_ANOTHER = ENV_VAR_MAPPED
+    await setup({
+      servicePath: resolve(__dirname),
+    })
+    const url = joinUrl(TEST_BASE_URL, '/dev/hello')
+    const response = await fetch(url)
+    json = await response.json()
+  })
+
+  // cleanup
+  afterAll(async () => {
+    process.env.ENV_VAR_QUOTED = undefined
+    process.env.ENV_VAR_UNQUOTED = undefined
+    process.env.ENV_VAR_MAPPED_FROM_ANOTHER = undefined
+    await teardown()
+  })
+
+  test('it should handle a quoted environment variable', async () => {
+    expect(json).toMatchObject({
+      ENV_VAR_QUOTED,
+    })
+  })
+
+  test('it should handle an unquoted environment variable', async () => {
+    expect(json).toMatchObject({
+      ENV_VAR_UNQUOTED,
+    })
+  })
+
+  test('it should handle a mapped environment variable', async () => {
+    expect(json).toMatchObject({
+      ENV_VAR_MAPPED,
+    })
+  })
+
+  test('it should handle an undefined quoted environment variable', async () => {
+    expect(json).toHaveProperty('ENV_VAR_EMPTY_STRING', undefined)
+  })
+
+  test('it should handle an undefined unquoted environment variable', async () => {
+    expect(json).toHaveProperty('ENV_VAR_UNDEFINED', undefined)
+  })
+})

tests/endToEnd/environmentVariables/handler.js

@@ -0,0 +1,24 @@
+'use strict'
+
+exports.hello = async () => {
+  const {
+    ENV_VAR_QUOTED,
+    ENV_VAR_UNQUOTED,
+    ENV_VAR_MAPPED,
+    ENV_VAR_EMPTY_STRING,
+    ENV_VAR_UNDEFINED,
+  } = process.env
+
+  const body = JSON.stringify({
+    ENV_VAR_QUOTED,
+    ENV_VAR_UNQUOTED,
+    ENV_VAR_MAPPED,
+    ENV_VAR_EMPTY_STRING, // This should be undefined
+    ENV_VAR_UNDEFINED, // This should be undefined
+  })
+
+  return {
+    statusCode: 200,
+    body,
+  }
+}

tests/endToEnd/environmentVariables/serverless.yml

@@ -0,0 +1,26 @@
+service: uncategorized-tests
+
+plugins:
+  - ../../../
+
+provider:
+  memorySize: 128
+  name: aws
+  region: us-east-1 # default
+  runtime: nodejs12.x
+  stage: dev
+  versionFunctions: false
+  environment:
+    ENV_VAR_QUOTED: "${env:ENV_VAR_QUOTED}"
+    ENV_VAR_UNQUOTED: ${env:ENV_VAR_UNQUOTED}
+    ENV_VAR_MAPPED: "${env:ENV_VAR_MAPPED_FROM_ANOTHER}"
+    ENV_VAR_EMPTY_STRING: "${env:ENV_VAR_EMPTY_STRING}"
+    ENV_VAR_UNDEFINED: ${env:ENV_VAR_UNDEFINED}
+
+functions:
+  hello:
+    handler: handler.hello
+    events:
+      - http:
+          method: get
+          path: /hello