feat: warn on missing environment variables

This adds a helper function which extracts values
from environment variables, and warns if they are
not set.

See conference-buddy#25

gatsby-node.js

@@ -1,7 +1,10 @@
 const { createClient } = require("@supabase/supabase-js")
+const { fromEnv } = require("./utils/fromEnv.js")
 
-const supabaseUrl = process.env.GATSBY_APP_SUPABASE_URL || "empty"
-const supabaseAnonKey = process.env.GATSBY_APP_SUPABASE_ANON_KEY || "empty"
+const { supabaseUrl, supabaseAnonKey } = fromEnv({
+  supabaseUrl: "GATSBY_APP_SUPABASE_URL",
+  supabaseAnonKey: "GATSBY_APP_SUPABASE_ANON_KEY",
+})(process.env)
 
 const supabase = createClient(supabaseUrl, supabaseAnonKey)
 

jest.config.js

@@ -16,7 +16,7 @@ module.exports = {
       "jest-transform-stub",
   },
   moduleNameMapper: {
-    "@/(.*)": "<rootDir>/src/$1",
+    "@/(.*)": "<rootDir>/$1",
   },
   preset: "ts-jest",
   testEnvironment: "jsdom",
@@ -26,7 +26,7 @@ module.exports = {
     "<rootDir>/tests/setup/setup-files.ts",
     "<rootDir>/tests/setup/setup-after-env.ts",
   ],
-  testMatch: ["<rootDir>/src/**/*.test.ts(x)"],
+  testMatch: ["<rootDir>/**/*.test.ts?(x)"],
   moduleDirectories: ["node_modules", "src"],
   testURL: `http://localhost`,
   moduleFileExtensions: ["ts", "tsx", "js", "jsx", "json", "node"],

supabaseClient.ts

@@ -1,8 +1,10 @@
 import { createClient } from "@supabase/supabase-js"
+import { fromEnv } from "./utils/fromEnv"
 
-const supabaseUrl: string = process.env.GATSBY_APP_SUPABASE_URL || "empty"
-const supabaseAnonKey: string =
-  process.env.GATSBY_APP_SUPABASE_ANON_KEY || "empty"
+const { supabaseUrl, supabaseAnonKey } = fromEnv({
+  supabaseUrl: "GATSBY_APP_SUPABASE_URL",
+  supabaseAnonKey: "GATSBY_APP_SUPABASE_ANON_KEY",
+})(process.env)
 
 const supabase = createClient(supabaseUrl, supabaseAnonKey)
 

tsconfig.json

@@ -15,6 +15,6 @@
     "noUnusedParameters": true,
     "removeComments": false
   },
-  "include": ["./src/**/*.ts", "./src/**/*.tsx"],
+  "include": ["./src/**/*.ts", "./src/**/*.tsx", "./utils/**/*.ts"],
   "exclude": ["node_modules", "setup-test-env.js"]
 }

utils/fromEnv.js

@@ -0,0 +1,9 @@
+// Pure-JS version of fromEnv.ts for Gatsby
+/** @type {import("./fromEnv").fromEnv } */
+exports.fromEnv = def => env =>
+  Object.entries(def).reduce((res, [defKey, envKey]) => {
+    const v = env[envKey]
+    if (v === undefined || v.length === 0)
+      throw new Error(`${envKey} is not defined in environment!`)
+    return { ...res, [defKey]: v }
+  }, {})

utils/fromEnv.test.ts

@@ -0,0 +1,14 @@
+import { fromEnv } from "./fromEnv"
+
+describe("fromEnv()", () => {
+  it("should return environment variables if defined", () => {
+    const env = { FOO: "bar" }
+    expect(fromEnv({ foo: "FOO" })(env)).toEqual({ foo: "bar" })
+  })
+  it("should throw an error if the environment variable is not defined", () => {
+    const env = {}
+    expect(() => fromEnv({ foo: "FOO" })(env)).toThrow(
+      "FOO is not defined in environment!"
+    )
+  })
+})

utils/fromEnv.ts

@@ -0,0 +1,9 @@
+export const fromEnv =
+  <T extends Record<string, string>>(def: T) =>
+  (env: NodeJS.ProcessEnv): Record<keyof T, string> =>
+    Object.entries(def).reduce((res, [defKey, envKey]) => {
+      const v = env[envKey]
+      if (v === undefined || v.length === 0)
+        throw new Error(`${envKey} is not defined in environment!`)
+      return { ...res, [defKey]: v }
+    }, {} as Record<keyof T, string>)