refactor: centralize WhatsApp config merging

src/config/merge-config.ts

@@ -0,0 +1,35 @@
+import type { ClawdbotConfig } from "./config.js";
+import type { WhatsAppConfig } from "./types.js";
+
+export type MergeSectionOptions<T> = {
+  unsetOnUndefined?: Array<keyof T>;
+};
+
+export function mergeConfigSection<T extends Record<string, unknown>>(
+  base: T | undefined,
+  patch: Partial<T>,
+  options: MergeSectionOptions<T> = {},
+): T {
+  const next: Record<string, unknown> = { ...(base ?? {}) };
+  for (const [key, value] of Object.entries(patch) as [keyof T, T[keyof T]][]) {
+    if (value === undefined) {
+      if (options.unsetOnUndefined?.includes(key)) {
+        delete next[key as string];
+      }
+      continue;
+    }
+    next[key as string] = value as unknown;
+  }
+  return next as T;
+}
+
+export function mergeWhatsAppConfig(
+  cfg: ClawdbotConfig,
+  patch: Partial<WhatsAppConfig>,
+  options?: MergeSectionOptions<WhatsAppConfig>,
+): ClawdbotConfig {
+  return {
+    ...cfg,
+    whatsapp: mergeConfigSection(cfg.whatsapp, patch, options),
+  };
+}