build: force the usage of t3-env and throw error on process.env usage

.eslintrc.cjs

@@ -4,7 +4,7 @@ const config = {
     parserOptions: {
         project: true
     },
-    plugins: ['@typescript-eslint'],
+    plugins: ['@typescript-eslint', 'eslint-plugin-n'],
     extends: [
         'plugin:@next/next/recommended',
         'plugin:@typescript-eslint/recommended-type-checked',
@@ -31,7 +31,13 @@ const config = {
             {
                 checksVoidReturn: { attributes: false }
             }
-        ]
+        ],
+
+        // In favor of type safety, the usage of `process.env` will throw an error.
+        // All references to `process.env` should be replaced with the `env` object created by
+        // the `@t3-oss/env-nextjs` package, which can be found at `src/env.js`.
+        // This ensures that the environment variables are properly validated and that the code is type-safe.
+        'n/no-process-env': 'error'
     }
 };
 

package.json

@@ -9,7 +9,7 @@
         "format": "prettier --write .",
         "jest:test": "SKIP_ENV_VALIDATION=1 jest",
         "jest:watch": "jest --watch",
-        "lint": "next lint",
+        "lint": "next lint --dir .",
         "playwright:test": "playwright test",
         "playwright:test:codegen": "playwright codegen",
         "playwright:test:debug": "playwright test --debug",
@@ -66,6 +66,7 @@
         "autoprefixer": "~10.4",
         "eslint": "~8.57",
         "eslint-config-next": "~14.2",
+        "eslint-plugin-n": "~17.3",
         "eslint-plugin-storybook": "~0.8",
         "husky": "~9.0",
         "jest": "~29.7",

playwright.config.ts

@@ -1,5 +1,7 @@
 import { defineConfig, devices } from '@playwright/test';
 
+import { env } from '~/env';
+
 /**
  * Read environment variables from file.
  * https://github.com/motdotla/dotenv
@@ -14,11 +16,11 @@ export default defineConfig({
     /* Run tests in files in parallel */
     fullyParallel: true,
     /* Fail the build on CI if you accidentally left test.only in the source code. */
-    forbidOnly: !!process.env.CI,
+    forbidOnly: env.CI,
     /* Retry on CI only */
-    retries: process.env.CI ? 2 : 0,
+    retries: env.CI ? 2 : 0,
     /* Opt out of parallel tests on CI. */
-    workers: process.env.CI ? 1 : undefined,
+    workers: env.CI ? 1 : undefined,
     /* Reporter to use. See https://playwright.dev/docs/test-reporters */
     reporter: 'html',
     /* Shared settings for all the projects below. See https://playwright.dev/docs/api/class-testoptions. */