articles to articlesList and slice and length functions for ArticlesModel to act like an array

src/blog/types/models.ts

@@ -36,11 +36,14 @@ export interface ArticleModel {
 }
 
 export interface ArticlesModel {
-  articles: ArticleModel[];
+  articlesList: ArticleModel[];
   articlesById: Record<string, ArticleModel>;
   // articlesByTag: Record<string, ArticleModel[]>;
   // articlesByAuthor: Record<string, ArticleModel[]>;
 
+  length: number;
+  slice(start: number, end?: number): ArticleModel[];
+
   refresh(list: ArticleModel[]): ArticlesModel;
   create(a: ArticleModel): ArticlesModel;
   readByIndex(index: number): ArticleModel | undefined;
@@ -50,13 +53,30 @@ export interface ArticlesModel {
 }
 
 // ---------- FACTORY ----------
-export function createArticlesModelObject(): ArticlesModel {
+export function createArticlesModelObject(
+  articles: ArticleModel[] = []
+): ArticlesModel {
+  const initialMap: Record<string, ArticleModel> = {};
+  for (const a of articles) {
+    if (a._id) initialMap[a._id] = a;
+  }
+
   return {
-    articles: [],
-    articlesById: {},
+    articlesList: articles,
+    articlesById: initialMap,
+
+    // --- computed property ---
+    get length() {
+      return this.articlesList.length;
+    },
+
+    // --- array-like slice ---
+    slice(start: number, end?: number) {
+      return this.articlesList.slice(start, end);
+    },
 
     refresh(list) {
-      this.articles = list;
+      this.articlesList = list;
 
       const map: Record<string, ArticleModel> = {};
       for (const a of list) {
@@ -67,13 +87,13 @@ export function createArticlesModelObject(): ArticlesModel {
     },
 
     create(a) {
-      this.articles = createInList(this.articles, a);
+      this.articlesList = createInList(this.articlesList, a);
       this.articlesById = createById(this.articlesById, a);
       return this;
     },
 
     readByIndex(index) {
-      return readInList(this.articles, index);
+      return readInList(this.articlesList, index);
     },
 
     readById(id) {
@@ -81,13 +101,13 @@ export function createArticlesModelObject(): ArticlesModel {
     },
 
     update(a) {
-      this.articles = updateInList(this.articles, a);
+      this.articlesList = updateInList(this.articlesList, a);
       this.articlesById = updateById(this.articlesById, a);
       return this;
     },
 
     delete(id) {
-      this.articles = deleteInList(this.articles, id);
+      this.articlesList = deleteInList(this.articlesList, id);
       this.articlesById = deleteById(this.articlesById, id);
       return this;
     }