feat(config): add env helper

packages/config/src/__tests__/env.test.ts

@@ -0,0 +1,40 @@
+import { afterAll, beforeEach, describe, expect, test } from 'vitest'
+
+import { env, PrismaConfigEnvError } from '../env'
+
+const VAR_NAME = 'PRISMA_CONFIG_ENV_TEST'
+const originalValue = process.env[VAR_NAME]
+
+describe('env', () => {
+  beforeEach(() => {
+    delete process.env[VAR_NAME]
+  })
+
+  afterAll(() => {
+    if (originalValue === undefined) {
+      delete process.env[VAR_NAME]
+    } else {
+      process.env[VAR_NAME] = originalValue
+    }
+  })
+
+  test('returns the value when the environment variable is defined', () => {
+    process.env[VAR_NAME] = 'postgresql://example'
+    expect(env(VAR_NAME)).toBe('postgresql://example')
+  })
+
+  test('throws when the environment variable is missing', () => {
+    expect(() => env(VAR_NAME)).toThrowError(PrismaConfigEnvError)
+    expect(() => env(VAR_NAME)).toThrowErrorMatchingInlineSnapshot(
+      `[PrismaConfigEnvError: Missing required environment variable: PRISMA_CONFIG_ENV_TEST]`,
+    )
+  })
+
+  test('throws when the environment variable is an empty string', () => {
+    process.env[VAR_NAME] = ''
+    expect(() => env(VAR_NAME)).toThrowError(PrismaConfigEnvError)
+    expect(() => env(VAR_NAME)).toThrowErrorMatchingInlineSnapshot(
+      `[PrismaConfigEnvError: Missing required environment variable: PRISMA_CONFIG_ENV_TEST]`,
+    )
+  })
+})

packages/config/src/env.ts

@@ -0,0 +1,14 @@
+export class PrismaConfigEnvError extends Error {
+  constructor(name: string) {
+    super(`Missing required environment variable: ${name}`)
+    this.name = 'PrismaConfigEnvError'
+  }
+}
+
+export function env(name: string): string {
+  const value = process.env[name]
+  if (!value) {
+    throw new PrismaConfigEnvError(name)
+  }
+  return value
+}

packages/config/src/index.ts

@@ -1,5 +1,6 @@
 export { defaultTestConfig } from './defaultTestConfig'
 export { defineConfig } from './defineConfig'
+export { env, PrismaConfigEnvError } from './env'
 export type { ConfigDiagnostic, ConfigFromFile, InjectFormatters, LoadConfigFromFileError } from './loadConfigFromFile'
 export { loadConfigFromFile } from './loadConfigFromFile'
 export { loadConfigFromPackageJson } from './loadConfigFromPackageJson'