release: WRNexusJS 0.4.0

packages/dev-server/src/watch.ts

@@ -8,13 +8,16 @@
  *                         process and HMR socket stay alive.
  */
 
-import { watch, type FSWatcher } from "node:fs";
+import { existsSync, statSync, watch, type FSWatcher } from "node:fs";
+import { isAbsolute, join, relative, resolve } from "node:path";
 import type { HmrHub } from "./hmr.ts";
 import type { DevAssetServer } from "./assets.ts";
 import type { DevToolbarCollector } from "@wrnexus/dev-toolbar/server";
 
 export interface WatchOptions {
   appDir: string;
+  /** Additional package component/runtime/style directories watched for HMR. */
+  extraDirs?: string[];
   hub: HmrHub;
   assets: DevAssetServer;
   devToolbarCollector?: DevToolbarCollector;
@@ -39,8 +42,12 @@ function classify(rel: string): Kind {
   return "server";
 }
 
-/** Returns the watcher so the running server can close it during shutdown. */
-export function startWatcher(opts: WatchOptions): FSWatcher | undefined {
+export interface WatchHandle {
+  close(): void;
+}
+
+/** Returns a composite watcher so the running server can close every source root. */
+export function startWatcher(opts: WatchOptions): WatchHandle | undefined {
   const { appDir, hub, assets } = opts;
   const pending = new Set<Kind>();
   const pendingFiles = new Set<string>();
@@ -72,18 +79,45 @@ export function startWatcher(opts: WatchOptions): FSWatcher | undefined {
     pendingFiles.clear();
   };
 
-  try {
-    return watch(appDir, { recursive: true }, (_event, filename) => {
-      if (!filename) return;
-      const rel = filename.toString().replace(/\\/g, "/");
-      if (isIgnored(rel)) return;
-      pendingFiles.add(rel);
-      pending.add(classify(rel));
-      if (timer) clearTimeout(timer);
-      timer = setTimeout(flush, 200); // debounce editor write bursts
-    });
-  } catch (err) {
-    console.warn("[wrnexus] file watching unavailable; HMR disabled", err);
-    return undefined;
+  const appRoot = resolve(appDir);
+  const candidates = [appRoot, ...(opts.extraDirs ?? []).map((dir) => resolve(dir))];
+  const roots = [...new Set(candidates)]
+    .filter((dir) => existsSync(dir) && statSync(dir).isDirectory())
+    .filter(
+      (dir, index, values) =>
+        !values.some((other, otherIndex) => {
+          if (otherIndex >= index) return false;
+          const nested = relative(other, dir);
+          return nested === "" || (!nested.startsWith("..") && !isAbsolute(nested));
+        }),
+    );
+  const watchers: FSWatcher[] = [];
+
+  for (const root of roots) {
+    try {
+      const external = root !== appRoot;
+      watchers.push(
+        watch(root, { recursive: true }, (_event, filename) => {
+          if (!filename) return;
+          const relativeFile = filename.toString().replace(/\\/g, "/");
+          if (isIgnored(relativeFile)) return;
+          const file = external ? join(root, relativeFile).replace(/\\/g, "/") : relativeFile;
+          pendingFiles.add(file);
+          pending.add(classify(file));
+          if (timer) clearTimeout(timer);
+          timer = setTimeout(flush, 200); // debounce editor write bursts
+        }),
+      );
+    } catch (error) {
+      console.warn(`[wrnexus] file watching unavailable for ${root}`, error);
+    }
   }
+
+  if (!watchers.length) return undefined;
+  return {
+    close() {
+      if (timer) clearTimeout(timer);
+      for (const watcher of watchers) watcher.close();
+    },
+  };
 }