feat: initial webapp structure from notion2site

lib/get-env.ts

@@ -0,0 +1,17 @@
+export function getEnv(
+  key: string,
+  defaultValue?: string,
+  env = process.env
+): string {
+  const value = env[key]
+
+  if (value !== undefined) {
+    return value
+  }
+
+  if (defaultValue !== undefined) {
+    return defaultValue
+  }
+
+  throw new Error(`Config error: missing required env var "${key}"`)
+}