i

src/api/StorageManager.js

@@ -76,12 +76,15 @@ export class StorageManager extends ApiClient {
   #articleIndexCache = null;
   /** @type {Map<string, object>} sku → article detail */
   #articlesBySku = new Map();
-  /** @type {Map<string, Set<() => void>>} sku → refreshers */
+  /** @type {Map<string, Set<(article: object) => void>>} sku → article listeners */
+  #articleWatchers = new Map();
+  /** @type {Map<string, Set<() => void>>} sku → history refreshers */
   #historyWatchers = new Map();
 
   constructor(baseUrl = window.location.origin) {
     super(baseUrl);
     this.#initCaches();
+    this.article.watch = (sku, onArticle) => this.watchArticle(sku, onArticle);
   }
 
   /** Settled article detail for sku, or undefined. */
@@ -93,7 +96,12 @@ export class StorageManager extends ApiClient {
   setArticle(article) {
     requireObject(article, 'article');
     requireDefined(article.sku, 'article.sku');
-    this.#articlesBySku.set(String(article.sku), article);
+    const key = String(article.sku);
+    this.#articlesBySku.set(key, article);
+    const watchers = this.#articleWatchers.get(key);
+    if (watchers) {
+      for (const onArticle of watchers) onArticle(article);
+    }
     return article;
   }
 
@@ -108,6 +116,42 @@ export class StorageManager extends ApiClient {
     return this.setArticle(res.article);
   }
 
+  /**
+   * Subscribe to article detail updates (local setArticle + SSE `article-<sku>`).
+   * @param {string} sku
+   * @param {(article: object) => void} onArticle
+   * @returns {{ article: object | null, unwatch: () => void }}
+   */
+  watchArticle(sku, onArticle) {
+    const key = String(sku);
+    const needListen = !this.#articleWatchers.has(key) && !this.#historyWatchers.has(key);
+
+    let watchers = this.#articleWatchers.get(key);
+    if (!watchers) {
+      watchers = new Set();
+      this.#articleWatchers.set(key, watchers);
+    }
+    watchers.add(onArticle);
+    if (needListen) {
+      this.#events?.addEventListener(`article-${key}`, this.#onArticleSignal);
+    }
+
+    return {
+      article: this.getArticle(key) ?? null,
+      unwatch: () => {
+        const set = this.#articleWatchers.get(key);
+        if (!set) return;
+        set.delete(onArticle);
+        if (set.size === 0) {
+          this.#articleWatchers.delete(key);
+          if (!this.#historyWatchers.has(key)) {
+            this.#events?.removeEventListener(`article-${key}`, this.#onArticleSignal);
+          }
+        }
+      },
+    };
+  }
+
   /**
    * Parsed category map + root id from settled caches, or null if any piece missing.
    * @returns {{ categories: object, rootCategoryId: unknown } | null}
@@ -153,13 +197,17 @@ export class StorageManager extends ApiClient {
         notifyError(err);
       });
 
+    const needListen = !this.#articleWatchers.has(key) && !this.#historyWatchers.has(key);
+
     let watchers = this.#historyWatchers.get(key);
     if (!watchers) {
       watchers = new Set();
       this.#historyWatchers.set(key, watchers);
-      this.#events?.addEventListener(`article-${key}`, this.#onArticleHistorySignal);
     }
     watchers.add(run);
+    if (needListen) {
+      this.#events?.addEventListener(`article-${key}`, this.#onArticleSignal);
+    }
 
     run();
 
@@ -170,16 +218,22 @@ export class StorageManager extends ApiClient {
       set.delete(run);
       if (set.size === 0) {
         this.#historyWatchers.delete(key);
-        this.#events?.removeEventListener(`article-${key}`, this.#onArticleHistorySignal);
+        if (!this.#articleWatchers.has(key)) {
+          this.#events?.removeEventListener(`article-${key}`, this.#onArticleSignal);
+        }
       }
     };
   }
 
-  #onArticleHistorySignal = (event) => {
+  #onArticleSignal = (event) => {
     const sku = event.type.slice('article-'.length);
-    const watchers = this.#historyWatchers.get(sku);
-    if (!watchers) return;
-    for (const run of watchers) run();
+    if (this.#articleWatchers.has(sku)) {
+      void this.loadArticle(sku).catch((err) => notifyError(err));
+    }
+    const historyWatchers = this.#historyWatchers.get(sku);
+    if (historyWatchers) {
+      for (const run of historyWatchers) run();
+    }
   };
 
   /** Patch local articleIndex name if already loaded; no-op otherwise. */
@@ -261,8 +315,11 @@ export class StorageManager extends ApiClient {
         console.error('[storageMgr] articles SSE refresh failed', err);
       });
     });
-    for (const sku of this.#historyWatchers.keys()) {
-      es.addEventListener(`article-${sku}`, this.#onArticleHistorySignal);
+    for (const sku of new Set([
+      ...this.#articleWatchers.keys(),
+      ...this.#historyWatchers.keys(),
+    ])) {
+      es.addEventListener(`article-${sku}`, this.#onArticleSignal);
     }
     es.onerror = () => {
       console.error('[storageMgr] events stream error');